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CSEC Physics study materials
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CSEC Physics practice questions

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Question 1Mechanics and Motion

A car travels 150 m due east in 30 s. What is its average velocity?

  1. 4500 m/s due east
  2. 180 m/s due east
  3. 5.0 m/s due east Correct answer.
  4. 0.20 m/s due east

Explanation

Average velocity equals displacement divided by time, so 150 m ÷ 30 s = 5.0 m/s. The direction of the velocity is the direction of the displacement, which is due east.

Question 2Mechanics and Motion

Which quantity is a vector?

  1. Mass
  2. Temperature
  3. Distance
  4. Acceleration Correct answer.

Explanation

A vector has both magnitude and direction. Acceleration has a magnitude and acts in a definite direction, so it is a vector, whereas mass, temperature, and distance are scalars.

Question 3Mechanics and Motion

A stone falls freely from rest near the Earth's surface. Taking g = 10 m/s², how far does it fall in the first 3 s?

  1. 30 m
  2. 15 m
  3. 45 m Correct answer.
  4. 90 m

Explanation

For motion from rest under constant acceleration, s = ½gt². Substituting gives s = ½ × 10 × 3² = 45 m.

Question 4Mechanics and Motion

What does the gradient of a distance–time graph represent?

  1. Acceleration
  2. Total distance
  3. Force
  4. Speed Correct answer.

Explanation

On a distance–time graph the vertical change divided by the horizontal change gives the rate of change of distance, which is speed. A steeper gradient therefore indicates a faster-moving object.

Question 5Mechanics and Motion

A body moves in a straight line with constant velocity. What is its acceleration?

  1. Constant but non-zero
  2. Equal to its velocity
  3. Increasing steadily
  4. Zero Correct answer.

Explanation

Acceleration is the rate of change of velocity. If the velocity is constant, it is not changing, so the acceleration is zero.

Question 6Mechanics and Motion

Which instrument is used to measure the mass of a small object accurately in the laboratory?

  1. Beam balance Correct answer.
  2. Metre rule
  3. Vernier calliper
  4. Spring balance

Explanation

A beam balance compares an unknown mass with standard masses and gives a reading in kilograms, independent of the local value of g. A spring balance measures weight, which depends on gravity.

Question 7Mechanics and Motion

A cyclist moves at a steady 4 m/s for 10 s and then at a steady 8 m/s for 5 s, all in the same direction. What is the average speed for the whole journey?

  1. 5.3 m/s Correct answer.
  2. 6.0 m/s
  3. 4.8 m/s
  4. 12 m/s

Explanation

Total distance = (4 × 10) + (8 × 5) = 40 + 40 = 80 m, and total time = 15 s. Average speed = 80 ÷ 15 ≈ 5.3 m/s.

Question 8Mechanics and Motion

A force of 60 N acts on a mass of 12 kg on a frictionless surface. What is the acceleration produced?

  1. 720 m/s²
  2. 0.2 m/s²
  3. 72 m/s²
  4. 5 m/s² Correct answer.

Explanation

Newton's second law gives a = F/m. Dividing 60 N by 12 kg yields 5 m/s².

Question 9Mechanics and Motion

A book rests on a horizontal table. Which pair of forces forms an action–reaction pair according to Newton's third law?

  1. The book's weight and the normal force from the table on the book
  2. The book's weight and the gravitational pull of the book on the Earth Correct answer.
  3. The normal force on the book and the book's weight
  4. The book's weight and the friction between book and table

Explanation

Action–reaction pairs act on different bodies and are of the same type. The Earth pulls the book down gravitationally, and the book pulls the Earth up gravitationally with an equal force.

Question 10Mechanics and Motion

A resultant force of 24 N acts on a 6 kg trolley that is initially at rest. What is its velocity after 5 s?

  1. 120 m/s
  2. 4 m/s
  3. 20 m/s Correct answer.
  4. 0.8 m/s

Explanation

First find acceleration: a = F/m = 24/6 = 4 m/s². Then v = u + at = 0 + 4 × 5 = 20 m/s.

Question 11Mechanics and Motion

An object of weight 50 N is pulled along a rough horizontal floor at constant speed by a horizontal force of 18 N. What is the coefficient of friction between the object and the floor?

  1. 50
  2. 0.18
  3. 0.36 Correct answer.
  4. 2.8

Explanation

At constant speed the pulling force equals the friction, so friction = 18 N. Since friction = μN and N = weight = 50 N, μ = 18/50 = 0.36.

Question 12Mechanics and Motion

A ball is thrown vertically upward with a speed of 20 m/s. Taking g = 10 m/s² and ignoring air resistance, what is the maximum height reached?

  1. 20 m Correct answer.
  2. 10 m
  3. 40 m
  4. 2 m

Explanation

At the highest point the velocity is zero, so using v² = u² − 2gs gives 0 = 400 − 20s, hence s = 20 m.

Question 13Mechanics and Motion

A velocity–time graph shows a straight line starting at 10 m/s and falling to 2 m/s over 4 s. What is the displacement during this interval?

  1. 32 m
  2. 12 m
  3. 8 m
  4. 24 m Correct answer.

Explanation

Displacement is the area under the graph, which for this trapezium is ½(10 + 2) × 4 = 24 m. Alternatively, constant acceleration of −2 m/s² acting over 4 s gives the same result.

Question 14Mechanics and Motion

A force of 30 N acts at 60° to the horizontal on a box. What is the horizontal component of the force?

  1. 30 N
  2. 52 N
  3. 15 N Correct answer.
  4. 26 N

Explanation

The horizontal component is F cos θ = 30 × cos 60° = 30 × 0.5 = 15 N. The vertical component would be F sin θ.

Question 15Mechanics and Motion

Two forces of 6 N and 8 N act at right angles to each other at a point. What is the magnitude of their resultant?

  1. 48 N
  2. 10 N Correct answer.
  3. 14 N
  4. 2 N

Explanation

Perpendicular forces combine by the Pythagorean rule: R = √(6² + 8²) = √100 = 10 N.

Question 16Mechanics and Motion

A body moves in a circle at constant speed. Which statement about its motion is correct?

  1. Its acceleration is zero because its speed is constant
  2. Its acceleration points along the tangent to the circle
  3. Its velocity is constant because the speed is constant
  4. Its acceleration points toward the centre of the circle Correct answer.

Explanation

Although the speed is constant, the direction of motion changes continuously, so the velocity changes. This change is directed toward the centre, producing centripetal acceleration.

Question 17Mechanics and Motion

A box of mass 5 kg rests on a horizontal floor. Taking g = 10 N/kg, what is the normal reaction force from the floor on the box?

  1. 0.5 N
  2. 50 N Correct answer.
  3. 5 N
  4. 100 N

Explanation

On a horizontal surface with no vertical acceleration, the normal force balances the weight. Weight = mg = 5 × 10 = 50 N, so the normal reaction is 50 N.

Question 18Mechanics and Motion

A parachutist falls and eventually reaches terminal velocity. What is true at terminal velocity?

  1. The weight is greater than the air resistance
  2. The parachutist's acceleration equals g
  3. The air resistance exceeds the weight
  4. The air resistance equals the weight and the acceleration is zero Correct answer.

Explanation

Terminal velocity occurs when the upward drag force grows to equal the downward weight, giving zero resultant force. With zero resultant force the acceleration is zero and the speed stays constant.

Question 19Mechanics and Motion

A student measures the time for 20 oscillations of a simple pendulum as 40 s. What is the period of the pendulum?

  1. 20 s
  2. 2.0 s Correct answer.
  3. 0.5 s
  4. 800 s

Explanation

The period is the time for one complete oscillation. Dividing the total time by the number of oscillations gives 40 ÷ 20 = 2.0 s.

Question 20Mechanics and Motion

A car accelerates uniformly from rest and covers 100 m in 10 s. What is its acceleration?

  1. 20 m/s²
  2. 2.0 m/s² Correct answer.
  3. 1.0 m/s²
  4. 10 m/s²

Explanation

Using s = ut + ½at² with u = 0 gives 100 = ½ × a × 100, so a = 2.0 m/s². The final speed would then be 20 m/s.

Question 21Mechanics and Motion

A block is placed on a smooth inclined plane that makes an angle θ with the horizontal. Which expression gives the component of the block's weight acting down the slope?

  1. mg sin θ Correct answer.
  2. mg cos θ
  3. mg tan θ
  4. mg

Explanation

Resolving the weight along the slope gives mg sin θ, while the component perpendicular to the slope is mg cos θ. The down-slope component drives the acceleration on a frictionless incline.

Question 22Mechanics and Motion

Two masses, 3 kg and 5 kg, are connected by a light string over a frictionless pulley. Taking g = 10 m/s², what is the acceleration of the system?

  1. 2.5 m/s² Correct answer.
  2. 1.25 m/s²
  3. 5 m/s²
  4. 10 m/s²

Explanation

The net driving force is the weight difference, (5 − 3) × 10 = 20 N, and the total mass moved is 8 kg. Acceleration = 20/8 = 2.5 m/s².

Question 23Mechanics and Motion

A projectile is launched horizontally at 15 m/s from a cliff 45 m high. Taking g = 10 m/s² and ignoring air resistance, how far from the base of the cliff does it land?

  1. 67.5 m
  2. 15 m
  3. 30 m
  4. 45 m Correct answer.

Explanation

Vertical fall: 45 = ½ × 10 × t², so t = 3 s. Horizontal distance = horizontal speed × time = 15 × 3 = 45 m.

Question 24Mechanics and Motion

A force–time graph shows a constant force of 12 N acting on a 4 kg body for 3 s. What is the change in momentum of the body?

  1. 9 kg m/s
  2. 12 kg m/s
  3. 144 kg m/s
  4. 36 kg m/s Correct answer.

Explanation

Impulse equals the area under a force–time graph, which is 12 × 3 = 36 N s. By the impulse–momentum theorem this equals the change in momentum, 36 kg m/s.

Question 25Mechanics and Motion

A body of mass 2 kg moving at 6 m/s collides head-on with a stationary body of mass 4 kg, and they stick together. What is their common velocity after the collision?

  1. 2 m/s Correct answer.
  2. 6 m/s
  3. 3 m/s
  4. 4 m/s

Explanation

Momentum is conserved: (2 × 6) + 0 = (2 + 4) × v. So 12 = 6v, giving v = 2 m/s in the original direction of motion.

Question 26Mechanics and Motion

A student records the length of a metal rod as 24.6 cm using a metre rule. Which statement about this measurement is correct?

  1. The reading has three significant figures and an uncertainty of about 1 cm.
  2. The reading has two significant figures and an uncertainty of about 0.01 cm.
  3. The reading has two significant figures and an uncertainty of about 0.5 cm.
  4. The reading has three significant figures and an uncertainty of about 0.1 cm. Correct answer.

Explanation

A metre rule is normally read to the nearest millimetre, so the last digit recorded (0.1 cm place) is the limit of reading and the uncertainty is about half a division, roughly 0.1 cm. All three digits in 24.6 cm are meaningful, so the value has three significant figures.

Question 27Mechanics and Motion

A runner completes one lap of a circular track of circumference 400 m and returns to the starting point. Which statement about the runner's displacement and distance is correct?

  1. Displacement is 400 m and distance travelled is 0 m.
  2. Displacement is 400 m and distance travelled is 400 m.
  3. Displacement is 0 m and distance travelled is 0 m.
  4. Displacement is 0 m and distance travelled is 400 m. Correct answer.

Explanation

Displacement is a vector measured from the starting point to the finishing point; since the runner returns to the start, the displacement is zero. Distance is a scalar measuring the total path length covered, which here is the full circumference of 400 m.

Question 28Mechanics and Motion

Which quantity is obtained by calculating the area under a speed–time graph?

  1. The change in direction
  2. The acceleration
  3. The distance travelled Correct answer.
  4. The average speed

Explanation

On a speed–time graph, speed multiplied by time gives distance, so the area beneath the line represents the distance travelled. The gradient of the same graph gives acceleration, which is a different quantity.

Question 29Mechanics and Motion

A newton is equivalent to which combination of base SI units?

  1. kg m² s⁻²
  2. kg m s⁻² Correct answer.
  3. kg m s⁻¹
  4. kg m⁻¹ s⁻²

Explanation

From Newton's second law, force equals mass times acceleration, so the unit is kg × m/s², written kg m s⁻². This follows directly from F = ma with mass in kilograms and acceleration in metres per second squared.

Question 30Mechanics and Motion

A car travelling at 25 m/s brakes uniformly and stops in 5.0 s. What is the magnitude of its deceleration?

  1. 125 m/s²
  2. 0.20 m/s²
  3. 5.0 m/s² Correct answer.
  4. 2.5 m/s²

Explanation

Deceleration equals the change in velocity divided by the time taken: (25 − 0)/5.0 = 5.0 m/s². The velocity falls by 25 m/s in 5 s, so the rate of change is 5 m/s².

Question 31Mechanics and Motion

A stone is dropped from rest and falls freely for 3.0 s. Taking g = 10 m/s² and ignoring air resistance, how far does it fall?

  1. 15 m
  2. 30 m
  3. 90 m
  4. 45 m Correct answer.

Explanation

Using s = ut + ½at² with u = 0, a = 10 m/s² and t = 3.0 s gives s = ½ × 10 × 9 = 45 m. The distance depends on the square of the time, not simply on speed multiplied by time.

Question 32Mechanics and Motion

A force of 18 N acts on a 3.0 kg object that is already moving at 4.0 m/s in the direction of the force. What is the object's speed after 2.0 s?

  1. 22 m/s
  2. 6.0 m/s
  3. 10 m/s
  4. 16 m/s Correct answer.

Explanation

The acceleration is a = F/m = 18/3.0 = 6.0 m/s², so the velocity increases by 6.0 × 2.0 = 12 m/s. Adding this to the initial 4.0 m/s gives a final speed of 16 m/s.

Question 33Mechanics and Motion

A 4.0 kg block slides down a smooth plane inclined at 30° to the horizontal. Taking g = 10 m/s², what is the acceleration of the block along the plane?

  1. 10 m/s²
  2. 2.0 m/s²
  3. 5.0 m/s² Correct answer.
  4. 8.7 m/s²

Explanation

On a smooth incline the only force along the slope is the component of weight, mg sin θ, so the acceleration is g sin θ. With θ = 30°, sin 30° = 0.5, giving 10 × 0.5 = 5.0 m/s².

Question 34Mechanics and Motion

Two forces of 5 N and 12 N act in opposite directions along the same line on a body. What is the magnitude of the resultant force?

  1. 17 N
  2. 7 N Correct answer.
  3. 60 N
  4. 13 N

Explanation

When two forces act along the same line but in opposite directions, their resultant is the difference of their magnitudes: 12 − 5 = 7 N. The resultant acts in the direction of the larger force.

Question 35Mechanics and Motion

A uniform metre rule is pivoted at its centre and balances when a 2.0 N weight hangs 20 cm from the pivot on the left. How far from the pivot on the right must a 4.0 N weight be placed to keep balance?

  1. 10 cm Correct answer.
  2. 5.0 cm
  3. 40 cm
  4. 20 cm

Explanation

For balance about the pivot, the moments must be equal: 2.0 × 20 = 4.0 × d, so d = 40/4.0 = 10 cm. A larger weight needs a shorter distance to produce the same moment.

Question 36Mechanics and Motion

A body of mass 3.0 kg moving at 8.0 m/s collides with a stationary body of mass 5.0 kg, and the two stick together. What is their common velocity after the collision?

  1. 5.0 m/s
  2. 4.8 m/s
  3. 3.0 m/s Correct answer.
  4. 8.0 m/s

Explanation

Momentum is conserved: (3.0 × 8.0) + 0 = (3.0 + 5.0) × v, so 24 = 8.0v and v = 3.0 m/s. The combined mass is larger, so the common velocity is less than the original 8.0 m/s.

Question 37Mechanics and Motion

A worker pushes a crate at constant velocity across a level floor using a horizontal force of 40 N. What is the magnitude of the friction force acting on the crate?

  1. Less than 40 N but not zero
  2. 40 N Correct answer.
  3. Zero, because the crate is moving
  4. More than 40 N

Explanation

Constant velocity means the net horizontal force is zero, so the friction force must exactly balance the applied force. Friction therefore has magnitude 40 N, directed opposite to the motion.

Question 38Mechanics and Motion

A ball is thrown horizontally at 12 m/s from the top of a tower and lands 60 m from the base. Taking g = 10 m/s² and ignoring air resistance, what is the height of the tower?

  1. 60 m
  2. 30 m
  3. 250 m
  4. 125 m Correct answer.

Explanation

Horizontal and vertical motions are independent. The time of flight is t = 60/12 = 5.0 s, and the vertical fall is h = ½gt² = ½ × 10 × 25 = 125 m.

Question 39Mechanics and Motion

An object hangs at rest from a spring balance calibrated in newtons, and the balance reads 24 N. On the Moon, where gravitational field strength is about one-sixth that on Earth, what would the balance read for the same object?

  1. 144 N
  2. 24 N
  3. 4.0 N Correct answer.
  4. 0 N

Explanation

A spring balance measures the weight, W = mg, which depends on the local gravitational field strength. On the Moon g is about one-sixth of Earth's value, so the reading falls to 24/6 = 4.0 N, while the mass stays the same.

Question 40Mechanics and Motion

A vehicle of mass 1200 kg travelling at 20 m/s is brought to rest by a constant braking force in 8.0 s. What is the magnitude of the braking force?

  1. 150 N
  2. 24000 N
  3. 3000 N Correct answer.
  4. 9600 N

Explanation

The deceleration is 20/8.0 = 2.5 m/s², and Newton's second law gives F = ma = 1200 × 2.5 = 3000 N. Equivalently, the rate of change of momentum is (1200 × 20)/8.0 = 3000 N.

Question 41Heat and Thermal Physics

A student places a metal spoon in a cup of hot water. After a short time the handle of the spoon feels warm. Which process transfers thermal energy along the spoon?

  1. Radiation emitted by the spoon towards the hand
  2. Evaporation of water from the spoon surface
  3. Convection currents inside the solid metal
  4. Conduction through the metal lattice and free electrons Correct answer.

Explanation

In a solid, thermal energy is transferred by particles vibrating and passing energy to neighbours, and in metals free electrons carry energy rapidly. Convection needs a moving fluid, and radiation does not require the spoon to conduct heat along its length, so conduction is the process responsible.

Question 42Heat and Thermal Physics

Which statement correctly describes the transfer of thermal energy by radiation?

  1. It is stopped completely by a single sheet of clear glass.
  2. It occurs only from cooler objects to hotter objects.
  3. It travels as electromagnetic waves and can pass through a vacuum. Correct answer.
  4. It requires a material medium to carry the energy.

Explanation

Thermal radiation is infrared electromagnetic radiation, so it needs no medium and can cross empty space, which is how energy reaches Earth from the Sun. All objects above absolute zero emit radiation, and net transfer is from hotter to cooler bodies.

Question 43Heat and Thermal Physics

A liquid is heated in a beaker. Coloured specks suspended in the liquid move upwards near the flame and downwards near the cooler sides. This circulation is an example of which process?

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

Explanation

Heating makes the liquid expand and become less dense, so it rises while cooler, denser liquid sinks to replace it, forming convection currents. Conduction in a liquid is slow because the particles are far apart, and radiation plays only a minor part in this arrangement.

Question 44Heat and Thermal Physics

Which physical quantity is measured in joules per kilogram per kelvin, J kg⁻¹ K⁻¹?

  1. Thermal conductivity
  2. Rate of heat loss
  3. Specific heat capacity Correct answer.
  4. Specific latent heat

Explanation

Specific heat capacity is the energy needed to raise the temperature of one kilogram of a substance by one kelvin, giving units of joules per kilogram per kelvin. Specific latent heat has units of joules per kilogram because no temperature change occurs during a change of state.

Question 45Heat and Thermal Physics

What is meant by the specific latent heat of fusion of ice?

  1. The total energy released when 1 kg of ice cools to 0 °C
  2. The energy needed to turn 1 kg of water into steam at 100 °C
  3. The energy needed to melt 1 kg of ice at 0 °C without changing its temperature Correct answer.
  4. The energy needed to raise 1 kg of ice through 1 K

Explanation

Latent heat of fusion is the energy absorbed per kilogram when a solid changes to liquid at its melting point, with no change in temperature. The value for ice is about 3.34 × 10⁵ J kg⁻¹, and the temperature stays at 0 °C throughout melting.

Question 46Heat and Thermal Physics

A clinical thermometer is designed with a narrow constriction just above the bulb. What is the purpose of this constriction?

  1. To prevent the liquid from freezing in cold conditions
  2. To increase the range of temperatures that can be measured
  3. To slow the rate at which the thermometer responds to body heat
  4. To keep the liquid column from falling back before it is read Correct answer.

Explanation

When the thermometer is removed from the patient, the liquid contracts; the constriction breaks the column so the reading stays fixed until the thermometer is shaken. This lets a nurse read the temperature after the thermometer has been taken away from the patient.

Question 47Heat and Thermal Physics

Which of the following best explains why a metal lid that is stuck on a glass jar loosens when hot water is poured over the lid?

  1. The metal becomes softer and more flexible when heated.
  2. The metal expands more than the glass for the same temperature rise. Correct answer.
  3. The water dissolves the seal between the lid and the jar.
  4. The glass expands more than the metal for the same temperature rise.

Explanation

Metals have a larger coefficient of linear expansion than glass, so for the same temperature rise the lid expands more and its internal diameter increases, freeing it from the jar. The effect depends on the difference in expansion, not on softening or dissolving.

Question 48Heat and Thermal Physics

Two identical kettles are filled with equal masses of water. Kettle P is switched on for 5 minutes and kettle Q for 10 minutes. Assuming no heat losses, what is the ratio of the temperature rise in P to that in Q?

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

Explanation

For the same mass and substance, the temperature rise is proportional to the energy supplied, and energy supplied is power multiplied by time. Doubling the heating time doubles the energy, so the temperature rise in Q is twice that in P, giving a ratio of 1 : 2.

Question 49Heat and Thermal Physics

A 2.0 kg block of aluminium (specific heat capacity 900 J kg⁻¹ K⁻¹) is heated from 20 °C to 70 °C. How much energy is absorbed?

  1. 9.0 × 10⁴ J Correct answer.
  2. 1.8 × 10⁴ J
  3. 1.8 × 10⁵ J
  4. 4.5 × 10⁴ J

Explanation

Using E = mcΔθ gives E = 2.0 × 900 × 50 = 9.0 × 10⁴ J. The temperature change is 50 K, and the mass and specific heat capacity are multiplied by this change.

Question 50Heat and Thermal Physics

How much energy is required to melt 0.50 kg of ice at 0 °C? The specific latent heat of fusion of ice is 3.3 × 10⁵ J kg⁻¹.

  1. 3.3 × 10⁵ J
  2. 1.65 × 10⁵ J Correct answer.
  3. 6.6 × 10⁵ J
  4. 1.65 × 10⁶ J

Explanation

Energy for a change of state is E = mL, so E = 0.50 × 3.3 × 10⁵ = 1.65 × 10⁵ J. Because the ice is already at its melting point, no energy is needed to raise its temperature.