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MTLE Physics (Grades 9-12) study materials
MTLE Physics (Grades 9-12) study resources

MTLE Physics (Grades 9-12) practice questions

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Question 1Physics content knowledge (domains not enumerated in source)

A ball is thrown straight upward and reaches its highest point before falling back to the thrower's hand. At the highest point, what are the ball's velocity and acceleration?

  1. Velocity is zero; acceleration is zero.
  2. Velocity is directed downward; acceleration is directed downward.
  3. Velocity is zero; acceleration is directed downward and nonzero. Correct answer.
  4. Velocity is directed upward; acceleration is zero.

Explanation

At the top of the trajectory the instantaneous velocity is momentarily zero because the ball reverses direction. Gravity continues to act throughout the flight, so the acceleration remains g directed downward even at the highest point.

Question 2Physics content knowledge (domains not enumerated in source)

A 4.0 kg cart accelerates at 2.5 m/s² along a frictionless horizontal track. What net force acts on the cart?

  1. 40 N
  2. 6.5 N
  3. 10 N Correct answer.
  4. 1.6 N

Explanation

Newton's second law gives F = ma, so the net force equals 4.0 kg × 2.5 m/s² = 10 N. The result is in newtons because kilograms and meters per second squared are SI units.

Question 3Physics content knowledge (domains not enumerated in source)

Two identical resistors are connected in parallel across an ideal battery. Compared with connecting the same two resistors in series across the same battery, the parallel arrangement draws

  1. one quarter the current from the battery
  2. the same current from the battery
  3. four times the current from the battery Correct answer.
  4. half the current from the battery

Explanation

In series the equivalent resistance is 2R, while in parallel it is R/2, a factor of four smaller. Since current equals voltage divided by resistance, the parallel circuit draws four times the current of the series circuit.

Question 4Physics content knowledge (domains not enumerated in source)

A block slides down a frictionless incline of height h and is then brought to rest by friction on a horizontal surface. Ignoring air resistance, the total mechanical energy of the block–Earth system is best described as

  1. constant throughout because energy is always conserved
  2. constant during the slide and decreasing during the frictional stop Correct answer.
  3. increasing while the block slides because kinetic energy grows
  4. decreasing throughout the motion because the block slows

Explanation

On the frictionless incline only gravity does work, so mechanical energy is conserved while potential energy converts to kinetic energy. Once friction acts on the horizontal surface, it does negative work and converts mechanical energy into thermal energy, so the mechanical energy decreases.

Question 5Physics content knowledge (domains not enumerated in source)

A 1200 kg car traveling at 15 m/s collides head-on with a stationary 800 kg car, and the two lock together. What is their common speed immediately after the collision?

  1. 9.0 m/s Correct answer.
  2. 15 m/s
  3. 6.0 m/s
  4. 11 m/s

Explanation

Momentum is conserved in the collision: (1200 kg)(15 m/s) = (1200 kg + 800 kg)v. Solving gives v = 18000/2000 = 9.0 m/s in the original direction of motion.

Question 6Physics content knowledge (domains not enumerated in source)

A satellite moves in a circular orbit around Earth at constant speed. Which statement correctly describes the work done by gravity on the satellite during one quarter of an orbit?

  1. Gravity does positive work because the satellite moves.
  2. Gravity does zero work because the force is perpendicular to the velocity. Correct answer.
  3. Gravity does work equal to the gravitational potential energy.
  4. Gravity does negative work equal to the change in kinetic energy.

Explanation

In a circular orbit the gravitational force points toward Earth's center while the velocity is tangential, so the force is always perpendicular to the displacement. Work equals the dot product of force and displacement, which is zero here, consistent with the constant speed.

Question 7Physics content knowledge (domains not enumerated in source)

A simple pendulum has a period of 2.0 s on Earth. What is its approximate period on the Moon, where the free-fall acceleration is about one sixth that on Earth?

  1. 12 s
  2. 0.82 s
  3. 4.9 s Correct answer.
  4. 0.33 s

Explanation

The period of a simple pendulum is T = 2π√(L/g), so period varies as 1/√g. Reducing g by a factor of six increases the period by √6 ≈ 2.45, giving about 4.9 s.

Question 8Physics content knowledge (domains not enumerated in source)

A sound wave travels from air into water, where the speed of sound is greater. What happens to its frequency and wavelength?

  1. Frequency stays the same; wavelength increases. Correct answer.
  2. Frequency increases; wavelength stays the same.
  3. Frequency stays the same; wavelength decreases.
  4. Frequency decreases; wavelength increases.

Explanation

Frequency is set by the source and does not change when a wave crosses a boundary. Because v = fλ and the speed increases while frequency is fixed, the wavelength must increase in the faster medium.

Question 9Physics content knowledge (domains not enumerated in source)

A standing wave on a string fixed at both ends has nodes separated by 0.40 m. What is the wavelength of this standing wave?

  1. 0.20 m
  2. 0.40 m
  3. 0.60 m
  4. 0.80 m Correct answer.

Explanation

For a standing wave on a string, adjacent nodes are separated by half a wavelength. If that distance is 0.40 m, then λ/2 = 0.40 m and the wavelength is 0.80 m.

Question 10Physics content knowledge (domains not enumerated in source)

A concave mirror has a focal length of 20 cm. An object is placed 30 cm in front of the mirror. Where is the image formed?

  1. 60 cm behind the mirror
  2. 30 cm behind the mirror
  3. 60 cm in front of the mirror Correct answer.
  4. 12 cm in front of the mirror

Explanation

Using the mirror equation 1/f = 1/do + 1/di with f = 20 cm and do = 30 cm gives 1/di = 1/20 − 1/30 = 1/60, so di = 60 cm. A positive image distance for a concave mirror means a real image in front of the mirror.

Question 11Physics content knowledge (domains not enumerated in source)

Light of wavelength 500 nm passes through a double slit with a slit separation of 0.10 mm. What is the approximate angle to the first-order maximum?

  1. 0.50°
  2. 5.0°
  3. 2.9°
  4. 0.29° Correct answer.

Explanation

The double-slit condition is d sinθ = mλ, so sinθ = (1)(500×10⁻⁹ m)/(1.0×10⁻⁴ m) = 5.0×10⁻³. For small angles sinθ ≈ θ in radians, giving θ ≈ 0.005 rad, which is about 0.29°.

Question 12Physics content knowledge (domains not enumerated in source)

A photon of frequency f is absorbed by an atom that was in its ground state. Which expression gives the energy added to the atom?

  1. f/h
  2. hf Correct answer.
  3. hc/f
  4. hf/c

Explanation

The energy of a photon is given by the Planck relation E = hf, where h is Planck's constant and f is the frequency. When the photon is absorbed, that full energy is transferred to the atom.

Question 13Physics content knowledge (domains not enumerated in source)

In the photoelectric effect, increasing the intensity of incident light while keeping frequency above threshold changes which quantity?

  1. The threshold frequency of the metal
  2. The maximum kinetic energy of emitted electrons
  3. The number of photoelectrons emitted per second Correct answer.
  4. The stopping potential required to halt the current

Explanation

Intensity corresponds to the number of photons arriving per second, so more photons eject more electrons. The maximum kinetic energy and stopping potential depend on photon frequency, and the threshold frequency is a property of the metal.

Question 14Physics content knowledge (domains not enumerated in source)

A radioactive sample has a half-life of 8 days. What fraction of the original nuclei remains after 24 days?

  1. 1/3
  2. 1/6
  3. 1/2
  4. 1/8 Correct answer.

Explanation

Twenty-four days equals three half-lives because 24 ÷ 8 = 3. Each half-life halves the remaining nuclei, so the fraction left is (1/2)³ = 1/8.

Question 15Physics content knowledge (domains not enumerated in source)

In a nuclear fission reaction, a small amount of mass disappears and a large amount of energy is released. This is explained by

  1. the uncertainty principle relating energy and time
  2. E = mc², relating the mass defect to released energy Correct answer.
  3. the Pauli exclusion principle acting on nucleons
  4. the conservation of charge alone

Explanation

The products of fission have slightly less total rest mass than the reactants, and this mass defect appears as energy according to E = mc². Because c² is very large, a tiny mass difference yields a large energy release.

Question 16Physics content knowledge (domains not enumerated in source)

An ideal gas is compressed isothermally. Which statement describes the heat flow during the process?

  1. Heat flows out of the gas while the internal energy decreases.
  2. Heat flows out of the gas while the internal energy stays constant. Correct answer.
  3. No heat flows because the temperature is constant.
  4. Heat flows into the gas, and internal energy increases.

Explanation

For an ideal gas, internal energy depends only on temperature, so an isothermal process has zero change in internal energy. Work is done on the gas during compression, so by the first law the gas must release an equal amount of heat to its surroundings.

Question 17Physics content knowledge (domains not enumerated in source)

Two point charges are separated by a distance r. If the distance is doubled while the charges are unchanged, the electric force between them becomes

  1. one quarter as large Correct answer.
  2. four times as large
  3. half as large
  4. twice as large

Explanation

Coulomb's law states that the force is proportional to 1/r². Doubling the separation multiplies the denominator by four, so the force drops to one quarter of its original value.

Question 18Physics content knowledge (domains not enumerated in source)

A charged particle enters a uniform magnetic field with its velocity perpendicular to the field. The particle moves in a circular path because the magnetic force

  1. points along the velocity and accelerates the particle forward
  2. is always perpendicular to the velocity and changes only its direction Correct answer.
  3. does work on the particle and increases its speed
  4. increases with the particle's speed in a way that spirals it outward

Explanation

The magnetic force on a moving charge is qv × B, which is perpendicular to both the velocity and the field. A force perpendicular to velocity changes direction without changing speed, producing uniform circular motion.

Question 19Physics content knowledge (domains not enumerated in source)

A wire of length 0.50 m carries a current of 4.0 A perpendicular to a uniform magnetic field of 0.20 T. What is the magnitude of the magnetic force on the wire?

  1. 0.10 N
  2. 0.40 N Correct answer.
  3. 2.5 N
  4. 0.040 N

Explanation

The force on a current-carrying wire is F = BIL sinθ, and here the wire is perpendicular to the field so sinθ = 1. Multiplying 0.20 T × 4.0 A × 0.50 m gives 0.40 N.

Question 20Physics content knowledge (domains not enumerated in source)

A step-down transformer has 500 turns in the primary and 100 turns in the secondary. If the primary voltage is 120 V, what is the secondary voltage (ideal transformer)?

  1. 600 V
  2. 120 V
  3. 24 V Correct answer.
  4. 100 V

Explanation

For an ideal transformer, the voltage ratio equals the turns ratio: Vs/Vp = Ns/Np. Thus Vs = 120 V × (100/500) = 24 V, consistent with a step-down transformer.

Question 21Physics content knowledge (domains not enumerated in source)

A block of mass 2.0 kg is pushed 3.0 m along a rough horizontal floor by a horizontal force of 10 N while a friction force of 4 N opposes the motion. What is the net work done on the block?

  1. 12 J
  2. 30 J
  3. 42 J
  4. 18 J Correct answer.

Explanation

The net horizontal force is 10 N − 4 N = 6 N, and net work equals net force times displacement. Thus W = 6 N × 3.0 m = 18 J, which equals the change in kinetic energy.

Question 22Physics content knowledge (domains not enumerated in source)

A projectile is launched at 20 m/s at an angle of 30° above the horizontal on level ground, with air resistance neglected. What is the horizontal component of its initial velocity?

  1. 10 m/s
  2. 17 m/s Correct answer.
  3. 35 m/s
  4. 20 m/s

Explanation

The horizontal component is v₀cosθ = 20 m/s × cos30° ≈ 20 × 0.866 ≈ 17 m/s. This component stays constant throughout the flight because no horizontal force acts.

Question 23Physics content knowledge (domains not enumerated in source)

A 5.0 kg object hangs at rest from two vertical ropes. What is the tension in each rope?

  1. 5.0 N
  2. 49 N
  3. 98 N
  4. 24.5 N Correct answer.

Explanation

The total upward force from both ropes must balance the weight, mg = 5.0 kg × 9.8 m/s² = 49 N. With two identical vertical ropes sharing the load equally, each supports 24.5 N.

Question 24Physics content knowledge (domains not enumerated in source)

A container holds an ideal gas at constant volume. If the absolute temperature is increased from 300 K to 600 K, the pressure of the gas

  1. doubles Correct answer.
  2. stays the same
  3. quadruples
  4. halves

Explanation

At constant volume, Gay-Lussac's law states that pressure is directly proportional to absolute temperature. Doubling the absolute temperature from 300 K to 600 K therefore doubles the pressure.

Question 25Physics content knowledge (domains not enumerated in source)

An electron and a proton are accelerated through the same potential difference from rest. Which statement about their resulting de Broglie wavelengths is correct?

  1. The proton has the longer wavelength because it carries opposite charge.
  2. The electron has the longer wavelength because it gains less momentum. Correct answer.
  3. The proton has the longer wavelength because it is more massive.
  4. They have equal wavelengths because they gain equal kinetic energy.

Explanation

Both particles gain the same kinetic energy qV, but momentum p = √(2mK) is smaller for the less massive electron. Since λ = h/p, the smaller momentum gives the electron a longer de Broglie wavelength.

Question 26Physics content knowledge (domains not enumerated in source)

A ball is dropped from rest near Earth's surface with air resistance negligible. Which quantity increases by equal amounts in each successive second of fall?

  1. Mass
  2. Speed Correct answer.
  3. Acceleration
  4. Position

Explanation

With constant acceleration g, speed changes by g each second, so equal time intervals add equal amounts of speed. Position instead grows quadratically with time, and acceleration and mass stay constant.

Question 27Physics content knowledge (domains not enumerated in source)

A 1200 kg car accelerates uniformly from rest to 20 m/s in 8.0 s. What is the magnitude of the net force acting on the car?

  1. 150 N
  2. 9600 N
  3. 3000 N Correct answer.
  4. 2400 N

Explanation

Acceleration is Δv/Δt = 20/8.0 = 2.5 m/s². Newton's second law then gives F = ma = 1200 × 2.5 = 3000 N.

Question 28Physics content knowledge (domains not enumerated in source)

A 0.50 kg ball moving at 6.0 m/s strikes a wall and rebounds along the same line at 4.0 m/s. What is the magnitude of the impulse delivered to the ball by the wall?

  1. 5.0 N·s Correct answer.
  2. 3.0 N·s
  3. 1.0 N·s
  4. 11 N·s

Explanation

Impulse equals the change in momentum. Taking the initial direction as positive, Δp = m(v_f − v_i) = 0.50(−4.0 − 6.0) = −5.0 kg·m/s, so the magnitude is 5.0 N·s. The reversal of direction is why the speeds add rather than subtract.

Question 29Physics content knowledge (domains not enumerated in source)

A solid disk and a hoop have the same mass and radius and roll without slipping down the same incline from rest. Which object reaches the bottom first?

  1. The hoop, because it has more rotational inertia
  2. They arrive together, since both have the same radius
  3. The disk, because it has a smaller rotational inertia Correct answer.
  4. They arrive together, since both have the same mass

Explanation

A rolling object's acceleration depends on the ratio of rotational inertia to mr². The disk (½mr²) has a smaller ratio than the hoop (mr²), so more of its gravitational energy goes into translation and it accelerates faster.

Question 30Physics content knowledge (domains not enumerated in source)

A 2.0 kg block slides from rest down a frictionless incline and drops 1.5 m in height. What is its speed at the bottom?

  1. 5.4 m/s Correct answer.
  2. 7.7 m/s
  3. 3.8 m/s
  4. 29 m/s

Explanation

Conservation of energy gives ½mv² = mgh, so v = √(2gh) = √(2 × 9.8 × 1.5) ≈ 5.4 m/s. Mass cancels and the incline angle does not matter on a frictionless surface.

Question 31Physics content knowledge (domains not enumerated in source)

A uniform meter stick is pivoted at its center and balances. A 0.20 kg mass is hung 0.30 m to the left of the pivot. Where must a 0.30 kg mass be hung to keep the stick balanced?

  1. 0.45 m to the right of the pivot
  2. 0.15 m to the right of the pivot
  3. 0.30 m to the right of the pivot
  4. 0.20 m to the right of the pivot Correct answer.

Explanation

Balancing requires equal torques: 0.20 × 0.30 = 0.30 × d, so d = 0.20 m. The heavier mass must sit closer to the pivot to produce the same torque.

Question 32Physics content knowledge (domains not enumerated in source)

A hydraulic lift has a small piston of area 5.0 cm² and a large piston of area 200 cm². If a force of 40 N is applied to the small piston, what force is exerted by the large piston?

  1. 1600 N Correct answer.
  2. 160 N
  3. 8000 N
  4. 1.0 N

Explanation

Pascal's principle gives equal pressure, so F₂ = F₁(A₂/A₁) = 40 × (200/5.0) = 1600 N. The area ratio of 40 multiplies the applied force.

Question 33Physics content knowledge (domains not enumerated in source)

A block floats with 60 percent of its volume submerged in water. What is the density of the block?

  1. 600 kg/m³ Correct answer.
  2. 1000 kg/m³
  3. 400 kg/m³
  4. 1670 kg/m³

Explanation

For a floating object, the fraction submerged equals the ratio of the object's density to the fluid's density. Thus ρ = 0.60 × 1000 = 600 kg/m³.

Question 34Physics content knowledge (domains not enumerated in source)

A gas is taken through a complete cycle on a pressure–volume diagram and returns to its starting state. Which statement about the gas over one full cycle is correct?

  1. The change in internal energy is zero, and the net work done equals the net heat absorbed. Correct answer.
  2. The net heat absorbed is zero because the process is cyclic.
  3. The change in internal energy is positive because work is done.
  4. The net work done is zero because the gas returns to its initial state.

Explanation

Internal energy is a state function, so it returns to its initial value over a closed cycle and ΔU = 0. The first law then requires that the net heat absorbed equal the net work done, which is the area enclosed by the cycle.

Question 35Physics content knowledge (domains not enumerated in source)

Two identical waves traveling in opposite directions on the same string have the same amplitude and frequency. What is the amplitude of the resulting standing wave at a point where the two waves always arrive exactly out of phase?

  1. Zero Correct answer.
  2. Half the amplitude of one wave
  3. Twice the amplitude of one wave
  4. Equal to the amplitude of one wave

Explanation

Points of permanent destructive interference are nodes, where the displacements of the two waves cancel at every instant. The amplitude there is zero.

Question 36Physics content knowledge (domains not enumerated in source)

A pipe closed at one end and open at the other has a fundamental frequency of 200 Hz. What is the frequency of the next allowed harmonic?

  1. 400 Hz
  2. 600 Hz Correct answer.
  3. 800 Hz
  4. 300 Hz

Explanation

A pipe closed at one end supports only odd harmonics, so the allowed frequencies are 200, 600, 1000 Hz and so on. The next one above the fundamental is the third harmonic at 600 Hz.

Question 37Physics content knowledge (domains not enumerated in source)

A point charge of +2.0 μC is placed at a point where the electric potential is 500 V relative to infinity. What is the electric potential energy of this charge?

  1. 2.5 × 10⁻⁴ J
  2. 4.0 × 10⁻⁹ J
  3. 1.0 × 10⁻⁶ J
  4. 1.0 × 10⁻³ J Correct answer.

Explanation

Potential energy for a charge in a known potential is U = qV = (2.0 × 10⁻⁶)(500) = 1.0 × 10⁻³ J. The potential already accounts for the field of the other charges.

Question 38Physics content knowledge (domains not enumerated in source)

A 12 V battery is connected across two resistors of 4.0 Ω and 6.0 Ω in series. What is the current in the circuit?

  1. 5.0 A
  2. 2.0 A
  3. 1.2 A Correct answer.
  4. 0.83 A

Explanation

In series the resistances add: R = 4.0 + 6.0 = 10 Ω. Ohm's law then gives I = V/R = 12/10 = 1.2 A.

Question 39Physics content knowledge (domains not enumerated in source)

A resistor of 20 Ω dissipates 5.0 W of power. What is the current through it?

  1. 0.25 A
  2. 1.0 A
  3. 0.50 A Correct answer.
  4. 4.0 A

Explanation

Using P = I²R, I = √(P/R) = √(5.0/20) = √0.25 = 0.50 A. The power depends on the square of the current.

Question 40Physics content knowledge (domains not enumerated in source)

A coil of 200 turns and area 0.010 m² lies in a magnetic field that decreases uniformly from 0.50 T to zero in 0.10 s. What is the magnitude of the average induced emf?

  1. 100 V
  2. 10 V Correct answer.
  3. 0.10 V
  4. 1.0 V

Explanation

Faraday's law gives emf = N(ΔΦ/Δt) = 200 × (0.50 × 0.010)/0.10 = 10 V. The flux change is the field change times the coil area.

Question 41Physics content knowledge (domains not enumerated in source)

An object is placed 15 cm from a converging lens of focal length 10 cm. Where is the image formed?

  1. 30 cm on the opposite side of the lens Correct answer.
  2. 15 cm on the same side as the object
  3. 6.0 cm on the opposite side of the lens
  4. 10 cm on the opposite side of the lens

Explanation

The thin-lens equation gives 1/f = 1/d_o + 1/d_i, so 1/d_i = 1/10 − 1/15 = 1/30 and d_i = 30 cm. A positive image distance means a real image on the far side.

Question 42Physics content knowledge (domains not enumerated in source)

White light passes through a prism and spreads into a spectrum. Which property of the glass is responsible for the different bending of each color?

  1. The refractive index varies with wavelength Correct answer.
  2. The angle of incidence differs for each color
  3. The speed of light in vacuum varies with wavelength
  4. The prism absorbs some colors more than others

Explanation

Dispersion occurs because the refractive index of glass depends on wavelength, so each color refracts through a slightly different angle. This separates the colors spatially.

Question 43Physics content knowledge (domains not enumerated in source)

An electron in a hydrogen atom drops from the n = 3 level to the n = 2 level. Compared with the photon emitted in a drop from n = 4 to n = 2, the photon from the 3→2 transition has

  1. the same energy but a different frequency
  2. greater energy and longer wavelength
  3. greater energy and shorter wavelength
  4. less energy and longer wavelength Correct answer.

Explanation

The energy levels get closer together at higher n, so the 3→2 gap is smaller than the 4→2 gap. A smaller energy difference means a lower-energy photon and, since E = hc/λ, a longer wavelength.

Question 44Physics content knowledge (domains not enumerated in source)

A nucleus of carbon-14 undergoes beta-minus decay. What happens to its atomic number and mass number?

  1. Atomic number increases by 1; mass number decreases by 4
  2. Atomic number increases by 1; mass number is unchanged Correct answer.
  3. Atomic number is unchanged; mass number decreases by 1
  4. Atomic number decreases by 1; mass number is unchanged

Explanation

In beta-minus decay a neutron converts into a proton plus an emitted electron and antineutrino. The proton count rises by one while the total nucleon count stays the same, giving nitrogen-14.

Question 45Physics content knowledge (domains not enumerated in source)

A spring obeying Hooke's law is stretched 0.20 m by a force of 10 N. What is the elastic potential energy stored in the spring?

  1. 2.0 J
  2. 1.0 J Correct answer.
  3. 4.0 J
  4. 0.50 J

Explanation

The spring constant is k = F/x = 10/0.20 = 50 N/m. Stored energy is U = ½kx² = ½ × 50 × (0.20)² = 1.0 J.

Question 46Physics content knowledge (domains not enumerated in source)

A simple harmonic oscillator has an amplitude A. At what displacement from equilibrium is its kinetic energy equal to its potential energy?

  1. A/2
  2. A/√2 Correct answer.
  3. A/4
  4. A

Explanation

Total energy is ½kA², and potential energy is ½kx². Setting ½kx² equal to half the total gives x² = A²/2, so x = A/√2 ≈ 0.71A.

Question 47Physics content knowledge (domains not enumerated in source)

A 60 W incandescent bulb and a 12 W LED bulb produce about the same light output. Over 5.0 hours of use, how much more electrical energy does the incandescent bulb consume?

  1. 0.36 kWh
  2. 0.24 kWh Correct answer.
  3. 0.30 kWh
  4. 0.60 kWh

Explanation

The power difference is 60 − 12 = 48 W = 0.048 kW. Multiplying by 5.0 h gives 0.24 kWh of extra energy.

Question 48Physics content knowledge (domains not enumerated in source)

A spacecraft far from any planet fires its engine briefly and then coasts. According to Newton's first law, what happens to its motion after the engine shuts off?

  1. It immediately stops when the thrust ends
  2. It gradually slows down because no force pushes it forward
  3. It continues at constant velocity until another force acts on it Correct answer.
  4. It accelerates steadily in the direction of the burn

Explanation

With no net external force, an object maintains constant velocity, which includes both speed and direction. Motion does not require a continuing force to be sustained.

Question 49Physics content knowledge (domains not enumerated in source)

A 0.15 kg ball is thrown straight up with an initial speed of 12 m/s. Ignoring air resistance, how high does it rise?

  1. 3.7 m
  2. 1.2 m
  3. 7.3 m Correct answer.
  4. 14 m

Explanation

Using v² = v₀² − 2gh with v = 0 at the top gives h = v₀²/(2g) = 144/19.6 ≈ 7.3 m. The mass cancels out.

Question 50Physics content knowledge (domains not enumerated in source)

Two identical resistors are connected first in series and then in parallel across the same battery. What is the ratio of the power dissipated in the parallel combination to that in the series combination?

  1. 2:1
  2. 1:4
  3. 4:1 Correct answer.
  4. 1:2

Explanation

In series the resistance is 2R, and in parallel it is R/2, so the parallel resistance is one-quarter as large. Since P = V²/R at fixed voltage, the parallel combination dissipates four times the power.