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EEI CAST practice questions

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Question 1Mechanical reasoning, drawings, arithmetic and written instructions

In a first-class lever, where is the fulcrum positioned relative to the effort force and the load?

  1. The load is located between the fulcrum and the effort force
  2. The effort force is located between the fulcrum and the load
  3. The fulcrum is located between the effort force and the load Correct answer.
  4. The fulcrum and the load are located at the exact same point

Explanation

A first-class lever has its fulcrum positioned between the effort force and the resistance (load). Common trade examples include a crowbar, seesaw, and standard pliers, where the pivot sits between the applied force and the work being done.

Question 2Mechanical reasoning, drawings, arithmetic and written instructions

Which statement is always true regarding the mechanical advantage (MA) of an ideal second-class lever, such as a wheelbarrow?

  1. The mechanical advantage is always greater than 1 Correct answer.
  2. The mechanical advantage is always less than 1
  3. The mechanical advantage is always exactly equal to 1
  4. The mechanical advantage depends only on the weight of the load

Explanation

In a second-class lever, the load is located between the fulcrum and the effort force. Because the effort arm (distance from fulcrum to effort) is always longer than the load arm (distance from fulcrum to load), the mechanical advantage (effort arm / load arm) is always greater than 1, meaning less effort is needed to lift the load.

Question 3Mechanical reasoning, drawings, arithmetic and written instructions

A utility technician uses a 15-inch pipe wrench to loosen a stuck valve stem. If a second 30-inch pipe wrench is used instead, what effect does the longer handle have on the force required to generate the same torque?

  1. The required force is doubled
  2. The required force increases by four times
  3. The required force remains unchanged
  4. The required force is cut in half Correct answer.

Explanation

Torque is calculated as Force multiplied by distance (lever arm length), or T = F x d. If the distance d is doubled from 15 inches to 30 inches, the applied force F required to produce the identical torque is reduced by half (F = T / d).

Question 4Mechanical reasoning, drawings, arithmetic and written instructions

A lineworker uses a heavy pry bar as a first-class lever to lift an 800-pound transformer off a pad. The fulcrum is positioned 1 foot from the transformer, and the lineworker applies downward force at a handle position 4 feet from the fulcrum. Neglecting the weight of the bar, how much downward force must be applied to balance the load?

  1. 400 pounds
  2. 200 pounds Correct answer.
  3. 800 pounds
  4. 100 pounds

Explanation

By the law of the lever, Effort x Effort Arm = Load x Load Arm. Here, Effort x 4 ft = 800 lbs x 1 ft. Solving for Effort gives Effort = 800 / 4 = 200 pounds.

Question 5Mechanical reasoning, drawings, arithmetic and written instructions

Why can ideal third-class levers, with effort between fulcrum and load, be useful despite requiring greater effort force than load force?

  1. They reverse the direction of motion while eliminating all frictional resistance
  2. They multiply the distance and speed moved by the load at the expense of force Correct answer.
  3. They store mechanical potential energy indefinitely without continuous effort
  4. They allow an operator to exert less force than the actual weight of the load

Explanation

Third-class levers have the effort applied between the fulcrum and the load. While they require an effort force greater than the load (mechanical advantage < 1), a small movement of the effort produces a much larger, faster movement at the load end, maximizing speed, reach, and precision.

Question 6Mechanical reasoning, drawings, arithmetic and written instructions

To increase the mechanical advantage of a crowbar when prying up a heavy concrete conduit cover, which adjustment should the technician make?

  1. Move the fulcrum closer to the technician's hands
  2. Shorten the overall length of the crowbar handle
  3. Apply the effort force closer to the pivot point
  4. Move the fulcrum closer to the conduit cover Correct answer.

Explanation

Mechanical advantage for a lever equals the effort arm divided by the load arm. Moving the fulcrum closer to the load (conduit cover) shortens the load arm and lengthens the effort arm, substantially increasing the mechanical advantage and reducing the force required from the technician.

Question 7Mechanical reasoning, drawings, arithmetic and written instructions

A compound lever mechanism inside a heavy-duty cable crimper uses two stages: the first lever stage provides a mechanical advantage of 4:1, and the second connected lever stage provides an advantage of 6:1. Neglecting friction, what is the total mechanical advantage delivered at the crimping jaws?

  1. 24:1 Correct answer.
  2. 10:1
  3. 2:1
  4. 1.5:1

Explanation

In compound machine systems, the overall mechanical advantage is the product of the individual stage advantages. Here, total MA = MA1 x MA2 = 4 x 6 = 24:1. An applied hand force of 10 pounds results in 240 pounds of compressive force at the jaws.

Question 8Mechanical reasoning, drawings, arithmetic and written instructions

For the supplied uniform-section ideal cantilever crossarm with a single outer-tip load, where is the maximum magnitude of bending stress?

  1. At the exact midpoint between the pole and the outer tip
  2. At the outer tip directly beneath the insulator mount
  3. At the root where the crossarm attaches to the utility pole Correct answer.
  4. Uniformly distributed with equal stress at every point along the beam

Explanation

In a cantilever beam supported at one end and loaded at the free end, bending moment equals force times distance from the load point (M = F x x). The moment arm is greatest at the fixed attachment point (the root at the pole), resulting in the maximum bending moment and highest tensile and compressive stresses at that connection.

Question 9Mechanical reasoning, drawings, arithmetic and written instructions

A lineworker rigs a single fixed pulley at the top of a utility pole to hoist a crossarm. What is the ideal mechanical advantage (IMA) of this rigging setup?

  1. 2
  2. 3
  3. 0.5
  4. 1 Correct answer.

Explanation

A single fixed pulley changes only the direction of the applied pulling force and has an ideal mechanical advantage of 1. It provides no force reduction, so hoisting a 100-pound load requires pulling with 100 pounds of force (plus friction).

Question 10Mechanical reasoning, drawings, arithmetic and written instructions

How does adding a single movable pulley to a hoisting line change the lifting effort compared to using a single fixed pulley?

  1. It doubles the required pulling force because the rope must travel twice as far
  2. It halves the pulling force because two rope strands share the load Correct answer.
  3. It eliminates the need for rope travel while keeping the required force the same
  4. It quadruples the lifting speed without changing the required pulling force

Explanation

A single movable pulley moves with the load and is supported by two parts of line. Because the weight of the load is divided equally between the two supporting strands, the effort required to lift the load is cut in half (IMA = 2).

Question 11Mechanical reasoning, drawings, arithmetic and written instructions

A block and tackle system with four supporting rope strands is used to lift a 1,200-pound distribution transformer. Assuming an ideal system with zero friction, how much pulling force must the winch exert?

  1. 300 pounds Correct answer.
  2. 600 pounds
  3. 400 pounds
  4. 1,200 pounds

Explanation

The ideal mechanical advantage of a block and tackle equals the number of rope strands directly supporting the movable block and load. With 4 supporting strands, Effort = Load / 4 = 1,200 / 4 = 300 pounds.

Question 12Mechanical reasoning, drawings, arithmetic and written instructions

A rigging crew uses a 3:1 mechanical advantage pulley system to raise an underground pull box. If the ground crew pulls 18 feet of rope through the system, how high is the pull box raised?

  1. 9 feet
  2. 18 feet
  3. 6 feet Correct answer.
  4. 54 feet

Explanation

In any machine, work input equals work output (neglecting friction): Force_in x Distance_in = Force_out x Distance_out. With a 3:1 mechanical advantage, the load moves one-third the distance of the pulled rope: 18 ft / 3 = 6 feet.

Question 13Mechanical reasoning, drawings, arithmetic and written instructions

In the stated otherwise ideal pulley calculation, why does adding sheave friction and rope-bending resistance increase the actual required effort?

  1. Atmospheric air resistance against the moving rope significantly counteracts the line tension
  2. The weight of the fixed upper block attached to the boom adds directly to the lifted payload
  3. Sheave bearing friction and rope bending resistance consume part of the effort Correct answer.
  4. The mechanical advantage decreases steadily as the load moves higher off the ground

Explanation

Real mechanical systems have an efficiency of less than 100% due to friction between the sheave bearings and pins, as well as the internal resistance of the rope as it bends over the sheaves. This friction requires extra input force beyond the ideal mechanical advantage.

Question 14Mechanical reasoning, drawings, arithmetic and written instructions

A sealed plastic float barely floats in a tank of fresh water, with most of its body below the surface. The same float is moved to a tank of heavy salt brine. How will it float in the brine?

  1. Higher, with less of its body below the surface Correct answer.
  2. Lower, with more of its body below the surface
  3. At exactly the same depth, because its weight has not changed
  4. It will sink, because salt makes water pull objects downward

Explanation

Adding salt makes water denser. A floating object settles only until it displaces its own weight of liquid (Archimedes' principle), so in a denser liquid it needs to push aside less volume and rides higher.

Question 15Mechanical reasoning, drawings, arithmetic and written instructions

A winch line pulling with 2,000 pounds of tension passes through a snatch block anchor to make a 90-degree turn. What is the total resultant load exerted on the snatch block and its anchor point?

  1. Exactly 2,000 pounds
  2. Exactly 4,000 pounds
  3. Approximately 1,414 pounds
  4. Approximately 2,828 pounds Correct answer.

Explanation

When a line changes direction around a snatch block, the resultant load on the block depends on the angle. At a 90-degree turn, the two 2,000-pound tension vectors are perpendicular. By vector addition (Pythagorean theorem), Resultant = sqrt(2,000^2 + 2,000^2) = 2,000 x sqrt(2) ≈ 2,828 pounds (or 1.414 times the line pull).

Question 16Mechanical reasoning, drawings, arithmetic and written instructions

Two sealed rigid cylinders contain equal amounts of the same ideal gas at equal temperature. Their internal volumes are2and1cubicfeet. How does pressure in the smaller compare?

  1. It is half the pressure in Cylinder A
  2. It is about twice the pressure in Cylinder A Correct answer.
  3. It is the same, because both cylinders hold the same amount of gas
  4. It is four times the pressure in Cylinder A

Explanation

At a constant temperature, the absolute pressure of a fixed amount of gas is inversely proportional to the space it occupies (Boyle's law: P1 x V1 = P2 x V2). The same gas squeezed into half the volume strikes the container walls about twice as often, so its pressure roughly doubles.

Question 17Mechanical reasoning, drawings, arithmetic and written instructions

If Gear A turns clockwise and meshes directly with Gear B, in which direction does Gear B rotate?

  1. Clockwise
  2. Alternating back and forth
  3. Counterclockwise Correct answer.
  4. It remains stationary unless a third gear is added

Explanation

Two external gears meshing directly together always rotate in opposite directions. Since Gear A rotates clockwise, Gear B must rotate counterclockwise.

Question 18Mechanical reasoning, drawings, arithmetic and written instructions

A gear train consists of three inline spur gears: Driver Gear A meshes with Idler Gear B, which meshes with Driven Gear C. If Gear A rotates counterclockwise, what is the rotation direction of Gear C?

  1. Counterclockwise Correct answer.
  2. Clockwise
  3. Gear C does not rotate
  4. The direction depends on the number of teeth on Idler B

Explanation

When an intermediate idler gear is placed between two gears, each mesh reverses rotation. Gear A (counterclockwise) causes Idler B to rotate clockwise, which in turn causes Gear C to rotate counterclockwise (the same direction as Gear A).

Question 19Mechanical reasoning, drawings, arithmetic and written instructions

A motor drives a 12-tooth gear at 1,800 RPM. This gear meshes directly with a 36-tooth gear connected to an oil pump. At what speed does the pump gear rotate?

  1. 5,400 RPM
  2. 1,200 RPM
  3. 900 RPM
  4. 600 RPM Correct answer.

Explanation

The relationship between gear teeth and speed is inverse: Speed_driver x Teeth_driver = Speed_driven x Teeth_driven. Here, 1,800 x 12 = Speed_driven x 36. Solving gives Speed_driven = 21,600 / 36 = 600 RPM.

Question 20Mechanical reasoning, drawings, arithmetic and written instructions

When a small high-speed drive gear meshes with a larger driven gear to achieve a 4:1 speed reduction, what happens to the output torque available at the driven shaft (assuming no friction losses)?

  1. The torque decreases by a factor of 4
  2. The torque increases by a factor of 4 Correct answer.
  3. The torque remains exactly the same
  4. The torque drops to zero because speed is lost

Explanation

Because mechanical power is the product of torque and rotational speed (Power = Torque x RPM), reducing the rotational speed by a factor of 4 results in a proportional 4-fold increase in output torque (Torque_out = 4 x Torque_in) under ideal conditions.

Question 21Mechanical reasoning, drawings, arithmetic and written instructions

Why are worm gear drives widely utilized in utility winches, cranes, and valve actuators?

  1. They operate at near 100% mechanical efficiency with less heat generation than any other gear type
  2. They allow the driven shaft to rotate at significantly higher speeds than the drive motor
  3. They give large speed reductions in a compact space and usually resist back-driving Correct answer.
  4. They allow instantaneous reversal of rotation without cutting input power

Explanation

A worm pair can provide a large reduction in compact space. Resistance to back-driving depends on geometry, friction, lubrication and conditions; it is not a universal self-locking guarantee or a substitute for engineered brakes and load protection. The choice identifies the common reduction characteristic, not a safe hoisting design.

Question 22Mechanical reasoning, drawings, arithmetic and written instructions

A utility air compressor uses a belt and pulley system. Pulley A has a 4-inch diameter and rotates at 1,200 RPM. It drives Pulley B, which has an 8-inch diameter. What is the rotational speed of Pulley B?

  1. 2,400 RPM
  2. 1,200 RPM
  3. 300 RPM
  4. 600 RPM Correct answer.

Explanation

For belt-driven pulleys, Diameter_driver x RPM_driver = Diameter_driven x RPM_driven. Thus, 4 in x 1,200 RPM = 8 in x RPM_driven. Solving gives RPM_driven = 4,800 / 8 = 600 RPM.

Question 23Mechanical reasoning, drawings, arithmetic and written instructions

Two workers carry a 120-pound steel beam on their shoulders, one at each end, with their shoulders 6 feet apart. The beam's center of gravity is 2 feet from Worker A and 4 feet from Worker B. How much of the weight does Worker A carry?

  1. 80 pounds Correct answer.
  2. 40 pounds
  3. 60 pounds
  4. 120 pounds

Explanation

Take moments about Worker B's shoulder: Worker A's force x 6 ft = 120 lb x 4 ft, so Worker A carries 480 / 6 = 80 pounds and Worker B carries the remaining 40 pounds. The person standing closer to the center of gravity always carries the larger share.

Question 24Mechanical reasoning, drawings, arithmetic and written instructions

A compound gear drive consists of two stages: Gear 1 (10 teeth) drives Gear 2 (40 teeth) on an intermediate shaft. Keyed to the same intermediate shaft is Gear 3 (15 teeth), which drives Gear 4 (60 teeth). What is the overall gear reduction ratio of this drive?

  1. 8:1
  2. 16:1 Correct answer.
  3. 6:1
  4. 4:1

Explanation

In a compound gear train, the overall ratio is the product of the individual stage ratios. Stage 1 ratio = 40 / 10 = 4:1. Stage 2 ratio = 60 / 15 = 4:1. Total gear ratio = 4 x 4 = 16:1. If the input shaft turns at 1,600 RPM, the output shaft turns at 100 RPM.

Question 25Mechanical reasoning, drawings, arithmetic and written instructions

Which fundamental scientific principle explains how hydraulic systems transmit pressure from a master cylinder to slave cylinders?

  1. Bernoulli's Principle
  2. Archimedes' Principle
  3. Ohm's Law
  4. Pascal's Principle Correct answer.

Explanation

Pascal's Principle states that pressure applied to an enclosed, incompressible fluid is transmitted equally and undiminished in all directions throughout the fluid and to the walls of its container.

Question 26Mechanical reasoning, drawings, arithmetic and written instructions

A hydraulic pump supplies oil at a pressure of 2,500 psi (pounds per square inch) to a boom lift cylinder. If the effective area of the cylinder piston is 6 square inches, how much total pushing force does the cylinder generate?

  1. 2,500 pounds
  2. 416.7 pounds
  3. 15,000 pounds Correct answer.
  4. 30,000 pounds

Explanation

Force generated by a hydraulic cylinder is calculated as Force = Pressure x Area (F = P x A). Here, F = 2,500 psi x 6 sq in = 15,000 pounds.

Question 27Mechanical reasoning, drawings, arithmetic and written instructions

A hydraulic jack has an input piston with a cross-sectional area of 2 square inches and an output lifting ram with an area of 20 square inches. If an operator applies 50 pounds of force to the input piston, how much weight can the lifting ram support?

  1. 500 pounds Correct answer.
  2. 100 pounds
  3. 1,000 pounds
  4. 250 pounds

Explanation

The pressure in the system is P = F_in / A_in = 50 lbs / 2 sq in = 25 psi. This identical pressure acts on the output piston: F_out = P x A_out = 25 psi x 20 sq in = 500 pounds (or F_out = F_in x (A_out / A_in) = 50 x 10 = 500 lbs).

Question 28Mechanical reasoning, drawings, arithmetic and written instructions

In the hydraulic jack described (input piston area = 2 sq in, output ram area = 20 sq in), if the operator pumps the input piston down a distance of 10 inches, how far does the output ram rise?

  1. 10.0 inches
  2. 1.0 inch Correct answer.
  3. 0.1 inch
  4. 5.0 inches

Explanation

Because hydraulic liquid is incompressible, the displaced fluid volume is conserved: Volume = Area_in x Distance_in = Area_out x Distance_out. Here, 2 sq in x 10 in = 20 cubic inches of oil displaced. The output ram rises: Distance_out = 20 cu in / 20 sq in = 1.0 inch.

Question 29Mechanical reasoning, drawings, arithmetic and written instructions

Water flows through a steady utility cooling pipe at a velocity of 2 feet per second. The pipe narrows from an internal diameter of 4 inches to a constricted section with an internal diameter of 2 inches. What is the velocity of the water in the constricted 2-inch section?

  1. 4 feet per second
  2. 1 foot per second
  3. 16 feet per second
  4. 8 feet per second Correct answer.

Explanation

By the continuity equation for incompressible fluids, Flow Rate Q = A1 x V1 = A2 x V2. Cross-sectional area is proportional to the square of diameter (A = pi x d^2 / 4). Halving the diameter from 4 in to 2 in reduces the cross-sectional area by a factor of 4 (4^2 / 2^2 = 16 / 4 = 4). Therefore, velocity must quadruple: 2 ft/s x 4 = 8 feet per second.

Question 30Mechanical reasoning, drawings, arithmetic and written instructions

A substation transformer cooling oil reservoir and a narrow sight glass column are connected at their bases. Both contain the same dielectric oil filled to an identical vertical height of 12 feet above the base. How does the hydrostatic pressure at the base of the wide reservoir compare to the pressure at the base of the narrow sight glass?

  1. The pressure is exactly identical at the base of both containers Correct answer.
  2. The pressure at the base of the wide reservoir is much greater because it contains more total weight of oil
  3. The pressure at the base of the narrow sight glass is higher due to capillary action
  4. Hydrostatic pressure cannot be determined without knowing the total volume of oil in each container

Explanation

Hydrostatic pressure at the bottom of a liquid column depends solely on fluid density and vertical column height (P = density x g x h), not on the shape, width, surface area, or total volume of the container. Because both columns contain the same oil at the same 12-foot height, the pressures at their bases are identical.

Question 31Mechanical reasoning, drawings, arithmetic and written instructions

When dragging a heavy steel junction box across a concrete floor, a technician notices it takes considerably more force to start the box moving than to keep it sliding at a steady speed. What explains this difference?

  1. The weight of the junction box decreases once it begins moving
  2. Air cushion pressure builds up underneath the box during movement
  3. Static friction is greater than kinetic (sliding) friction Correct answer.
  4. Kinetic friction is greater than static friction once the box starts moving

Explanation

Static friction (the resistance between two stationary surfaces in contact) is greater than kinetic or sliding friction (the resistance once motion begins). Once microscopic surface irregularities break free from interlocking, less continuous force is required to sustain movement.

Question 32Mechanical reasoning, drawings, arithmetic and written instructions

A line crew uses an inclined ramp to load a 600-pound cable drum onto a truck bed that is 3 feet high. If the ramp is 12 feet long, what is the ideal mechanical advantage (IMA) of this inclined plane?

  1. 3
  2. 4 Correct answer.
  3. 36
  4. 0.25

Explanation

The ideal mechanical advantage of an inclined plane equals the length of the slope divided by the vertical height (IMA = L / h). Here, IMA = 12 ft / 3 ft = 4.

Question 33Mechanical reasoning, drawings, arithmetic and written instructions

What happens to the overall center of gravity and stability of a utility bucket truck as the aerial boom is extended horizontally outward away from the chassis?

  1. The center of gravity moves lower toward the chassis, increasing vehicle stability
  2. The center of gravity stays in the exact center of the truck chassis regardless of boom extension
  3. Stability increases because the extended boom acts as a balancing counterweight
  4. The center of gravity shifts toward the boom, reducing stability and raising tipping risk Correct answer.

Explanation

For the stated extension with the support configuration otherwise unchanged, the load’s moment and combined center-of-gravity position can increase overturning risk toward the boom. Real stability depends on the rated configuration, ground, outriggers and loads. This conceptual comparison does not authorize a real truck movement or lift.

Question 34Mechanical reasoning, drawings, arithmetic and written instructions

A splitting wedge is essentially an application of which simple machine?

  1. Two inclined planes placed back to back Correct answer.
  2. A first-class lever with an internal fulcrum
  3. A screw turned about a central axis
  4. A wheel and axle

Explanation

A wedge consists of two inclined planes joined back-to-back. Driving the wedge forward converts linear input force along its length into substantial perpendicular splitting forces along its sloped faces.

Question 35Mechanical reasoning, drawings, arithmetic and written instructions

A screw mechanism has a lead (pitch) of 0.25 inches. If an operator turns the screw using a lever handle with a radius of 14 inches, what is the ideal mechanical advantage of this screw mechanism (use pi ≈ 3.14)?

  1. Approximately 56
  2. Approximately 88
  3. Approximately 352 Correct answer.
  4. Approximately 14

Explanation

A screw is an inclined plane wrapped around a cylinder. The ideal mechanical advantage equals the circumference traced by the effort arm divided by the screw lead: IMA = (2 x pi x r) / lead. Here, IMA = (2 x 3.14 x 14 in) / 0.25 in = 87.92 / 0.25 ≈ 351.7 (or 352).

Question 36Mechanical reasoning, drawings, arithmetic and written instructions

Which method of heat transfer occurs when thermal energy moves through a solid copper electrical busbar from a hot connection lug to cooler metal?

  1. Convection
  2. Conduction Correct answer.
  3. Radiation
  4. Induction

Explanation

Conduction is the transfer of heat through a stationary solid material via direct microscopic collisions between atoms and free electrons. Copper is an excellent thermal and electrical conductor.

Question 37Mechanical reasoning, drawings, arithmetic and written instructions

Why do overhead transmission line aluminum conductors sag significantly lower toward the ground on hot summer afternoons when carrying peak electrical loads?

  1. The electrical current increases the gravitational mass of the conductors, pulling them downward
  2. Air density decreases in hot weather, creating a partial vacuum that draws the wires downward
  3. Tensile strength increases in the heat, stretching the utility poles closer together
  4. Heat from the weather and the current lengthens the conductor through thermal expansion Correct answer.

Explanation

Metals expand when heated due to increased atomic vibration. On hot days with heavy electrical loading, ambient heat combined with I^2*R resistive heating raises conductor temperature, causing thermal elongation (expansion) of the line, which manifests as increased vertical sag between utility structures.

Question 38Mechanical reasoning, drawings, arithmetic and written instructions

A thermal-magnetic circuit breaker uses a bimetallic strip to trip during sustained electrical overloads. How does this strip function mechanically?

  1. One metal melts at a lower temperature, interrupting the circuit path like a fuse
  2. The magnetic field generated by the current repels the outer metal layer while attracting the inner layer
  3. Two bonded metals expand at different rates when heated, so the strip bends and releases a latch Correct answer.
  4. The two metals create a chemical battery voltage that signals a digital electronic release solenoid

Explanation

A bimetallic strip consists of two dissimilar metals bonded together. Because each metal has a different coefficient of thermal expansion, one metal expands more than the other when heated by excess current. This unequal expansion forces the composite strip to curve, physically pushing against a mechanical trip latch to open the breaker contacts.

Question 39Mechanical reasoning, drawings, arithmetic and written instructions

In a series electrical circuit containing three identical resistors connected to a 120-volt source, which statement correctly describes the electrical current and voltage?

  1. Current is the same through each resistor, and each resistor drops 40 volts Correct answer.
  2. The total current divides equally into thirds, while all three resistors experience the full 120 volts
  3. Both current and voltage divide equally into thirds at each sequential resistor
  4. Current increases after passing each resistor as electrical resistance is consumed

Explanation

In a series circuit, there is only a single path for electrical charge to flow, so current is identical at every point. The source voltage divides among series components according to Kirchhoff's Voltage Law: three identical resistors each drop 120 V / 3 = 40 volts.

Question 40Mechanical reasoning, drawings, arithmetic and written instructions

A lamp is connected to a battery through Switch C, which is in series with the whole circuit. Before Switch C, the circuit splits into two parallel branches, one containing Switch A and the other containing Switch B, and the branches rejoin before Switch C. If one switch is stuck open and cannot be closed, which stuck switch will keep the lamp dark no matter how the other switches are set?

  1. Switch A
  2. Switch B
  3. Switch C Correct answer.
  4. Any one of the three switches

Explanation

Current needs one complete path. Switches A and B are in parallel, so if either one is stuck open, current can still flow through the other branch. Switch C is in series with every path, so if it cannot close there is no alternate route and the lamp stays dark.

Question 41Mechanical reasoning, drawings, arithmetic and written instructions

Read the passage, then answer the question. New apprentices often find the first weeks of summer fieldwork exhausting. Crew leaders schedule lighter tasks during an apprentice's first several hot-weather shifts and add heavier work gradually. This gives the body time to acclimatize, so that by the third week most apprentices sweat more efficiently and tire less quickly in the heat. As used in the passage, the word acclimatize most nearly means:

  1. adjust to new conditions Correct answer.
  2. recover from an injury
  3. cool down after work
  4. learn a new skill

Explanation

Within the supplied passage, acclimatize means adjust to new conditions. This answers the vocabulary question, not a universal medical heat-acclimatization schedule or permission to ignore heat illness. Real work requires an appropriate heat-risk plan and response to symptoms.

Question 42Mechanical reasoning, drawings, arithmetic and written instructions

Read the passage, then answer the question. Beginning March 1, all crew members must sign in at the dispatch window before 6:45 a.m. Workers who arrive after 6:45 a.m. should report directly to the shift supervisor rather than to dispatch. This change will allow dispatch to finalize crew assignments before trucks begin leaving the yard at 7:00 a.m. What is the main purpose of this notice?

  1. To announce that trucks will now leave the yard earlier than before
  2. To explain why shift supervisors are replacing the dispatch office
  3. To warn workers that anyone arriving late will be disciplined
  4. To explain a new sign-in deadline and the reason for it Correct answer.

Explanation

The notice states a new rule (sign in before 6:45 a.m.), tells late arrivals what to do, and gives the reason (so dispatch can finalize assignments before trucks leave at 7:00 a.m.). Its purpose is to inform workers of a procedure change and explain it.

Question 43Mechanical reasoning, drawings, arithmetic and written instructions

Read the passage, then answer the question. Each storm-response vehicle must carry a restoration kit. The kit includes a first-aid box, two flashlights with spare batteries, a fire extinguisher, reflective traffic cones, and a printed list of emergency phone numbers. Drinking water and meals are provided at the staging site rather than stored in the vehicle. According to the passage, which item is NOT part of the restoration kit carried in the vehicle?

  1. A fire extinguisher
  2. Drinking water Correct answer.
  3. Reflective traffic cones
  4. A printed list of emergency phone numbers

Explanation

The last sentence says drinking water and meals are provided at the staging site rather than stored in the vehicle. The other three items appear in the list of kit contents. On NOT or EXCEPT questions, check each choice against the passage before answering.

Question 44Mechanical reasoning, drawings, arithmetic and written instructions

Read the passage, then answer the question. In winter, a thin coating of ice can turn an ordinary overhead conductor into a hazard. Ice that builds up unevenly can give the wire a lopsided shape that catches the wind like a wing. In a steady breeze, the conductor may begin galloping, swinging up and down in large, slow loops that can bring wires close enough to touch one another or damage hardware on the poles. As used in the passage, galloping refers to:

  1. the gradual stretching of a wire as it warms in the afternoon
  2. ice sliding off a conductor in large pieces
  3. the high-pitched humming a wire makes in light wind
  4. wind-driven up-and-down swinging of an iced wire Correct answer.

Explanation

The passage defines the term right after using it: the conductor swings up and down in large, slow loops, and the cause is wind acting on lopsided ice. Context clues that follow a word often explain its meaning.

Question 45Mechanical reasoning, drawings, arithmetic and written instructions

Read the passage, then answer the question. Wind turbines produce power only when the wind blows within a certain range of speeds. Because wind is intermittent, a wind farm may run near full output one hour and produce little the next. Grid operators therefore keep other resources, such as natural gas plants, hydroelectric dams, or large batteries, ready to fill the gaps. In the passage, the word intermittent most nearly means:

  1. extremely powerful
  2. coming and going irregularly Correct answer.
  3. predictable from hour to hour
  4. harmful to the environment

Explanation

The sentence explains the word through its effect: a wind farm may run near full output one hour and produce little the next. Something intermittent comes and goes rather than running steadily.

Question 46Mechanical reasoning, drawings, arithmetic and written instructions

Read the passage, then answer the question. We know how disruptive a power outage can be, especially during cold weather. Our crews have been working through the night to repair lines damaged by yesterday's storm. Most customers should have power restored by Thursday evening. If you see a downed line, stay well away from it and call our emergency number right away. The author's main purpose in this message is to:

  1. update customers on repairs and give a safety instruction Correct answer.
  2. persuade customers to buy backup generators for future storms
  3. explain the weather conditions that caused yesterday's storm
  4. apologize to customers for an increase in electricity rates

Explanation

The message updates customers on repair work and the expected restoration time, then tells them what to do if they see a downed line. It informs and instructs; it does not try to sell anything or discuss rates.

Question 47Mechanical reasoning, drawings, arithmetic and written instructions

Read the passage, then answer the question. The pole-climbing course runs for two weeks. During the first week, trainees practice on 20-foot poles in the training yard and must stay within reach of an instructor. In the second week, trainees who have passed the first-week skills check climb 40-foot poles. Trainees who do not pass the skills check repeat the first week before moving on. According to the passage, what must trainees do before they may climb 40-foot poles?

  1. Complete both weeks of the course
  2. Pass the first-week skills check Correct answer.
  3. Climb a 20-foot pole with no instructor nearby
  4. Repeat the first week of training

Explanation

The third sentence says that in the second week, trainees who have passed the first-week skills check climb 40-foot poles. Passing that check is the stated requirement.

Question 48Mechanical reasoning, drawings, arithmetic and written instructions

Read the passage, then answer the question. Attendance at the quarterly safety meeting is mandatory for all field employees. Employees who are on approved vacation must review the meeting recording within ten working days of their return. As used in the passage, the word mandatory most nearly means:

  1. required Correct answer.
  2. recommended
  3. scheduled
  4. optional

Explanation

Mandatory means required. The second sentence supports this: even employees on vacation must make up the meeting by reviewing the recording, which shows that attendance is not left to choice.

Question 49Mechanical reasoning, drawings, arithmetic and written instructions

Read the passage, then answer the question. A lightning strike heats the air along its path to temperatures several times hotter than the surface of the sun. The sudden heating makes the air expand violently, creating the shock wave we hear as thunder. Because light travels much faster than sound, people usually see the flash before they hear the thunder it caused. According to the passage, what causes thunder?

  1. Clouds colliding with one another during a storm
  2. Light from the flash striking the ground
  3. Rain falling quickly through cold air
  4. Air expanding suddenly after lightning heats it Correct answer.

Explanation

The second sentence states the cause: the sudden heating makes the air expand violently, creating the shock wave we hear as thunder. The passage also explains why the flash is seen before the thunder is heard.

Question 50Mechanical reasoning, drawings, arithmetic and written instructions

Read the passage, then answer the question. Engineers design critical substations with redundant equipment. Each major transformer has a backup that can carry the load if the first unit fails, and important control circuits are fed from two independent power supplies. Although this design costs more to build, it allows the substation to keep serving customers when a single component breaks down. In the passage, the word redundant most nearly means:

  1. outdated and due for replacement
  2. duplicated so that a backup is available Correct answer.
  3. unnecessary and wasteful
  4. designed to operate at reduced voltage

Explanation

In everyday speech redundant can mean unnecessary, but here the context describes backup transformers and two independent power supplies that keep service running if one part fails. In engineering, redundant equipment is a deliberate duplicate kept ready as a backup.