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Cameroon GCE A-Level Physics study materials
Cameroon GCE A-Level Physics study resources

Cameroon GCE A-Level Physics practice questions

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Question 1Mechanics

A body moves in a straight line with constant acceleration of 4 m/s². If it starts from rest, how far does it travel in the first 5 s?

  1. 50 m Correct answer.
  2. 20 m
  3. 10 m
  4. 100 m

Explanation

Using s = ut + ½at² with u = 0, a = 4 m/s² and t = 5 s gives s = ½ × 4 × 25 = 50 m. The displacement grows with the square of time, so doubling the time quadruples the distance.

Question 2Mechanics

Which quantity is a vector in linear motion?

  1. Distance
  2. Speed
  3. Time
  4. Displacement Correct answer.

Explanation

Displacement has both magnitude and direction, so it is a vector. Speed, distance and time are scalars with magnitude only, which is why displacement can be zero while distance travelled is not.

Question 3Mechanics

A stone is thrown vertically upwards with a speed of 20 m/s. Taking g = 10 m/s², what is the maximum height reached?

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

Explanation

At maximum height the velocity is zero, so using v² = u² − 2gh with v = 0 gives h = u²/(2g) = 400/20 = 20 m. The upward and downward journeys are symmetric in time when air resistance is neglected.

Question 4Mechanics

A force of 12 N acts on a mass of 3 kg on a frictionless surface. What is the acceleration produced?

  1. 9 m/s²
  2. 4 m/s² Correct answer.
  3. 0.25 m/s²
  4. 36 m/s²

Explanation

Newton's second law gives a = F/m, so a = 12/3 = 4 m/s². The acceleration is directly proportional to the resultant force and inversely proportional to the mass.

Question 5Mechanics

The SI unit of momentum is equivalent to which combination of base units?

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

Explanation

Momentum is mass times velocity, so its units are kg × m/s = kg m s⁻¹. This is also equivalent to N s, since a newton is a kg m s⁻² and multiplying by seconds gives kg m s⁻¹.

Question 6Mechanics

A body of weight 50 N rests on a horizontal surface. What is the normal reaction on the body?

  1. 25 N vertically upwards
  2. 0 N
  3. 50 N vertically upwards Correct answer.
  4. 50 N vertically downwards

Explanation

With no vertical acceleration, the vertical forces balance, so the normal reaction equals the weight in magnitude and acts vertically upwards. The weight acts downwards on the body while the reaction acts upwards on it.

Question 7Mechanics

Which statement correctly describes the moment of a force about a point?

  1. It is the product of the force and the perpendicular distance from the point to the line of action. Correct answer.
  2. It is the force divided by the perpendicular distance from the point.
  3. It is the product of the force and the distance moved by the body.
  4. It is the product of the force and the time for which it acts.

Explanation

The moment of a force is defined as force × perpendicular distance from the pivot to the line of action, measured in newton-metres. Using the perpendicular distance ensures only the component tending to rotate the body is counted.

Question 8Mechanics

A machine raises a load of 200 N through 3 m in 5 s. What is its average output power?

  1. 600 W
  2. 40 W
  3. 3000 W
  4. 120 W Correct answer.

Explanation

Work done is force × distance = 200 × 3 = 600 J, and power is work divided by time, giving 600/5 = 120 W. Power measures the rate of doing work, so the same work done faster needs greater power.

Question 9Mechanics

A car accelerates uniformly from 10 m/s to 30 m/s in 8 s. What is its acceleration?

  1. 5.0 m/s²
  2. 1.25 m/s²
  3. 2.5 m/s² Correct answer.
  4. 20 m/s²

Explanation

Acceleration is the change in velocity divided by the time taken: (30 − 10)/8 = 2.5 m/s². The change in velocity is 20 m/s, and dividing by the 8 s interval gives the rate of change.

Question 10Mechanics

A ball is projected horizontally at 15 m/s from a cliff 20 m high. Taking g = 10 m/s², how long does it take to reach the ground?

  1. 1.5 s
  2. 2.0 s Correct answer.
  3. 0.75 s
  4. 4.0 s

Explanation

Vertical motion is independent of the horizontal velocity, so using h = ½gt² gives 20 = 5t², hence t = 2.0 s. The horizontal speed of 15 m/s affects only the range, not the time of fall.

Question 11Mechanics

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

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

Explanation

Perpendicular forces combine by the Pythagorean theorem: R = √(6² + 8²) = √100 = 10 N. Adding magnitudes directly would only be valid if the forces acted along the same line.

Question 12Mechanics

A crate of mass 20 kg is pulled along a rough horizontal floor by a horizontal force of 90 N against a friction force of 30 N. What is its acceleration?

  1. 3 m/s² Correct answer.
  2. 1.5 m/s²
  3. 6 m/s²
  4. 4.5 m/s²

Explanation

The resultant force is 90 − 30 = 60 N, so a = F/m = 60/20 = 3 m/s². Friction always opposes motion, so it must be subtracted from the applied force before applying Newton's second law.

Question 13Mechanics

A trolley of mass 2 kg moving at 3 m/s collides with a stationary trolley of mass 1 kg and they move off together. What is their common velocity?

  1. 1.5 m/s
  2. 3 m/s
  3. 6 m/s
  4. 2 m/s Correct answer.

Explanation

Momentum is conserved: (2 × 3) + (1 × 0) = 3 × v, so v = 6/3 = 2 m/s. The combined mass is 3 kg, and dividing the total initial momentum by it gives the common velocity.

Question 14Mechanics

A uniform metre rule is pivoted at its centre. A 4 N weight hangs 20 cm from the pivot on one side. Where must a 2 N weight be placed on the other side to balance the rule?

  1. 10 cm from the pivot
  2. 20 cm from the pivot
  3. 40 cm from the pivot Correct answer.
  4. 80 cm from the pivot

Explanation

For balance the moments must be equal: 4 × 20 = 2 × d, so d = 40 cm. The smaller force needs a longer lever arm to produce the same turning effect.

Question 15Mechanics

A body of mass 5 kg is lifted vertically through 4 m at constant speed. Taking g = 10 m/s², what is the gain in gravitational potential energy?

  1. 0 J
  2. 200 J Correct answer.
  3. 50 J
  4. 20 J

Explanation

The gain in potential energy is mgh = 5 × 10 × 4 = 200 J. Lifting at constant speed means the applied force equals the weight, so the work done equals the potential energy gained.

Question 16Mechanics

A force of 20 N acts on a body for 0.5 s. What impulse does it deliver?

  1. 20 N s
  2. 40 N s
  3. 10 N s Correct answer.
  4. 0.025 N s

Explanation

Impulse equals force × time, so 20 × 0.5 = 10 N s. By the impulse–momentum theorem, this impulse equals the change in momentum of the body.

Question 17Mechanics

A cyclist moves round a circular track of radius 25 m at a constant speed of 10 m/s. What is the centripetal acceleration?

  1. 4 m/s² Correct answer.
  2. 2.5 m/s²
  3. 0.4 m/s²
  4. 250 m/s²

Explanation

Centripetal acceleration is v²/r = 100/25 = 4 m/s², directed towards the centre of the circle. Constant speed on a curved path still means acceleration because the direction of velocity changes.

Question 18Mechanics

A block slides down a rough incline at constant velocity. Which statement about the forces on the block is correct?

  1. The resultant force on the block is directed down the slope.
  2. The component of weight down the slope equals the frictional force up the slope. Correct answer.
  3. The frictional force is greater than the component of weight down the slope.
  4. The weight of the block equals the normal reaction.

Explanation

Constant velocity means zero acceleration and therefore zero resultant force. Along the slope, the downward component of weight is exactly balanced by friction acting up the slope.

Question 19Mechanics

A particle moves with simple harmonic motion of amplitude 0.10 m and period 2.0 s. What is its maximum speed?

  1. 0.05 m/s
  2. 0.63 m/s
  3. 0.31 m/s Correct answer.
  4. 0.10 m/s

Explanation

Angular frequency is ω = 2π/T = π rad/s, and maximum speed is ωA = π × 0.10 ≈ 0.31 m/s. The speed is greatest at the equilibrium position and zero at the extremes of the motion.

Question 20Mechanics

Two masses of 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. 10 m/s²
  2. 2.5 m/s² Correct answer.
  3. 5 m/s²
  4. 1.25 m/s²

Explanation

The net driving force is (5 − 3) × 10 = 20 N and the total mass moved is 8 kg, so a = 20/8 = 2.5 m/s². Both masses share the same magnitude of acceleration because the string is inextensible.

Question 21Mechanics

A ball of mass 0.2 kg strikes a wall horizontally at 10 m/s and rebounds at 6 m/s along the same line. What is the magnitude of the change in momentum?

  1. 1.2 kg m s⁻¹
  2. 3.2 kg m s⁻¹ Correct answer.
  3. 0.8 kg m s⁻¹
  4. 2.0 kg m s⁻¹

Explanation

Taking the initial direction as positive, the change is m(v − u) = 0.2 × (−6 − 10) = −3.2 kg m s⁻¹, so the magnitude is 3.2 kg m s⁻¹. Reversal of direction makes the velocity change 16 m/s, not 4 m/s.

Question 22Mechanics

A projectile is launched at 20 m/s at 30° above the horizontal. Taking g = 10 m/s², what is its horizontal range on level ground?

  1. 34.6 m Correct answer.
  2. 20.0 m
  3. 17.3 m
  4. 40.0 m

Explanation

Range is R = u² sin 2θ / g = 400 × sin 60° / 10 ≈ 34.6 m. The horizontal component is u cos 30° ≈ 17.3 m/s and the time of flight is 2u sin 30°/g = 2 s, whose product gives the same result.

Question 23Mechanics

A car of mass 1000 kg climbs a slope rising 1 m for every 10 m along the road at constant speed, against a total resistance of 500 N. Taking g = 10 m/s², what tractive force is needed?

  1. 1000 N
  2. 1500 N Correct answer.
  3. 5000 N
  4. 500 N

Explanation

The component of weight along the slope is mg sin θ = 1000 × 10 × 0.1 = 1000 N. Adding the 500 N resistance gives a required tractive force of 1500 N for constant speed.

Question 24Mechanics

A flywheel of moment of inertia 2 kg m² is accelerated uniformly from rest to 10 rad/s in 5 s. What torque acts on it?

  1. 20 N m
  2. 0.4 N m
  3. 4 N m Correct answer.
  4. 100 N m

Explanation

Angular acceleration is α = Δω/t = 10/5 = 2 rad/s², and torque is τ = Iα = 2 × 2 = 4 N m. This is the rotational analogue of Newton's second law, F = ma.

Question 25Mechanics

A particle in simple harmonic motion has amplitude 0.05 m and angular frequency 4 rad/s. At a displacement of 0.03 m from equilibrium, what is its speed?

  1. 0.20 m/s
  2. 0.12 m/s
  3. 0.16 m/s Correct answer.
  4. 0.08 m/s

Explanation

For SHM, v = ω√(A² − x²) = 4 × √(0.0025 − 0.0009) = 4 × 0.04 = 0.16 m/s. The speed is less than the maximum ωA = 0.20 m/s because the particle is away from equilibrium.

Question 26Mechanics

A stone is thrown vertically upwards with a speed of 20 m/s. Taking g = 10 m/s² and neglecting air resistance, what is the greatest height reached?

  1. 20 m Correct answer.
  2. 40 m
  3. 80 m
  4. 10 m

Explanation

At the highest point the velocity is zero, so using v² = u² - 2gh with v = 0 gives h = u²/(2g) = 400/20 = 20 m. The time to reach this height is 2 s, but only the height is asked.

Question 27Mechanics

Which of the following is a vector quantity?

  1. Time
  2. Mass
  3. Speed
  4. Displacement Correct answer.

Explanation

Displacement has both magnitude and direction, so it is a vector. Speed, mass and time have magnitude only and are scalars.

Question 28Mechanics

A body moves in a straight line with constant acceleration. Which graph of velocity against time represents this motion?

  1. A horizontal straight line
  2. A parabola
  3. A straight line through the origin
  4. A straight line not passing through the origin Correct answer.

Explanation

For constant acceleration, v = u + at, so the velocity–time graph is a straight line with gradient a and intercept u. If the initial velocity u is not zero, the line does not pass through the origin.

Question 29Mechanics

A force of 10 N acts on a body and moves it through a displacement of 3 m in the direction of the force. What is the work done by the force?

  1. 90 J
  2. 3.3 J
  3. 30 J Correct answer.
  4. 13 J

Explanation

Work done is the product of force and displacement in the direction of the force: W = F × d = 10 N × 3 m = 30 J. The other values arise from dividing or adding the quantities instead of multiplying.

Question 30Mechanics

Which statement correctly defines the centre of gravity of a body?

  1. The geometric centre of the body
  2. The point where the mass of the body is always concentrated
  3. The point through which the whole weight of the body always acts Correct answer.
  4. The point where the body is always in equilibrium

Explanation

The centre of gravity is the point through which the resultant weight of the body acts for all orientations of the body. It coincides with the centre of mass in a uniform gravitational field.

Question 31Mechanics

A body of mass 2 kg moves with a velocity of 5 m/s. What is its kinetic energy?

  1. 25 J Correct answer.
  2. 10 J
  3. 100 J
  4. 50 J

Explanation

Kinetic energy is given by KE = ½mv² = ½ × 2 × 5² = 25 J. The momentum of the body is 10 kg m/s, which is a different quantity.

Question 32Mechanics

A force of 12 N acts at a point on a body and its line of action passes through the pivot. What is the moment of the force about the pivot?

  1. 0 N m Correct answer.
  2. 6 N m
  3. 12 N m
  4. 24 N m

Explanation

The moment of a force about a point is the product of the force and the perpendicular distance from the point to the line of action. If the line of action passes through the pivot, the perpendicular distance is zero, so the moment is zero.

Question 33Mechanics

A body moves in a straight line with simple harmonic motion. At the equilibrium position, which quantity is maximum?

  1. Acceleration
  2. Displacement
  3. Speed Correct answer.
  4. Potential energy

Explanation

In simple harmonic motion, speed is maximum at the equilibrium position and zero at the extremes. Displacement, acceleration and potential energy are all zero at the equilibrium position.

Question 34Mechanics

A particle moves in a circle of radius 2.0 m at a constant speed of 4.0 m/s. What is its angular speed?

  1. 4.0 rad/s
  2. 2.0 rad/s Correct answer.
  3. 8.0 rad/s
  4. 0.5 rad/s

Explanation

Angular speed ω = v/r = 4.0/2.0 = 2.0 rad/s. The centripetal acceleration is v²/r = 8.0 m/s², which is a different quantity.

Question 35Mechanics

A body of mass 2 kg is moving at 3 m/s. A constant force of 4 N acts on it in the direction of motion for 2 s. What is its final speed?

  1. 5 m/s
  2. 7 m/s Correct answer.
  3. 14 m/s
  4. 11 m/s

Explanation

The impulse is F × t = 4 × 2 = 8 N s, so the change in momentum is 8 kg m/s. The change in velocity is 8/2 = 4 m/s, giving a final speed of 3 + 4 = 7 m/s.

Question 36Mechanics

A uniform metre rule of weight 1.0 N is supported at its centre. A 2.0 N weight is hung 20 cm from the centre on one side. At what distance from the centre on the other side must a 4.0 N weight be hung to balance the rule?

  1. 40 cm
  2. 20 cm
  3. 10 cm Correct answer.
  4. 5 cm

Explanation

Taking moments about the pivot: clockwise moment = 2.0 N × 20 cm = 40 N cm. For balance, 4.0 N × d = 40 N cm, so d = 10 cm. The weight of the rule acts at the centre and produces no moment.

Question 37Mechanics

A car of mass 800 kg is travelling at 20 m/s when the brakes are applied, bringing it to rest in a distance of 50 m. What is the average braking force?

  1. 12800 N
  2. 1600 N
  3. 3200 N Correct answer.
  4. 6400 N

Explanation

The kinetic energy is ½mv² = ½ × 800 × 20² = 160000 J. The work done by the braking force equals this energy, so F = 160000/50 = 3200 N. Alternatively, the deceleration is v²/(2s) = 400/100 = 4 m/s², giving F = ma = 800 × 4 = 3200 N.

Question 38Mechanics

Two forces of magnitudes 5 N and 12 N act at a point. Which of the following could be the magnitude of their resultant?

  1. 18 N
  2. 20 N
  3. 7 N Correct answer.
  4. 3 N

Explanation

The resultant of two forces lies between the difference and the sum of their magnitudes: 7 N ≤ R ≤ 17 N. Only 7 N lies within this range; the others are outside it.

Question 39Mechanics

A body of mass 2 kg is attached to a string and whirled in a vertical circle of radius 1.0 m. At the lowest point its speed is 5 m/s. Taking g = 10 m/s², what is the tension in the string at that point?

  1. 50 N
  2. 90 N
  3. 70 N Correct answer.
  4. 30 N

Explanation

At the lowest point, the tension acts upwards and the weight acts downwards, so T - mg = mv²/r. Thus T = mg + mv²/r = 20 + 2×25/1 = 20 + 50 = 70 N.

Question 40Mechanics

A body is in equilibrium under the action of three coplanar forces. Which condition must be satisfied?

  1. The forces must be parallel
  2. The vector sum of the forces must be zero Correct answer.
  3. The lines of action must be concurrent
  4. The forces must be equal in magnitude

Explanation

For a body to be in translational equilibrium, the vector sum of all forces acting on it must be zero. For rotational equilibrium, the sum of moments about any point must also be zero.

Question 41Mechanics

A body of mass 0.5 kg moving at 4 m/s collides head-on with a stationary body of mass 1.5 kg. After the collision, the two bodies move together. What is their common velocity?

  1. 1.0 m/s Correct answer.
  2. 2.0 m/s
  3. 0.5 m/s
  4. 3.0 m/s

Explanation

By conservation of momentum, total momentum before = 0.5 × 4 = 2 kg m/s. After collision, total mass = 2.0 kg, so common velocity = 2/2.0 = 1.0 m/s.

Question 42Mechanics

A particle of mass 0.2 kg moves in simple harmonic motion with amplitude 0.10 m and period 0.5 s. What is the maximum force acting on the particle?

  1. 3.16 N Correct answer.
  2. 0.32 N
  3. 6.32 N
  4. 1.26 N

Explanation

The angular frequency is ω = 2π/T = 2π/0.5 = 4π rad/s. The maximum acceleration is a_max = ω²A = (4π)² × 0.10 ≈ 15.8 m/s². Thus the maximum force is F = ma = 0.2 × 15.8 ≈ 3.16 N.

Question 43Mechanics

A flywheel of moment of inertia 0.50 kg m² rotates at 20 rad/s. A constant braking torque of 2.0 N m is applied. How many revolutions does the flywheel make before coming to rest?

  1. 25
  2. 4.0
  3. 16
  4. 8.0 Correct answer.

Explanation

The angular deceleration is α = τ/I = 2.0/0.50 = 4.0 rad/s². Using ω² = ω₀² - 2αθ gives θ = ω₀²/(2α) = 400/8 = 50 rad. Since 1 revolution = 2π rad, the number of revolutions is 50/(2π) ≈ 8.0.

Question 44Mechanics

A body is projected with speed u at an angle θ to the horizontal. Neglecting air resistance, which statement about its motion is correct?

  1. The vertical component of velocity is constant
  2. The horizontal component of velocity changes uniformly with time
  3. The maximum height is attained when the vertical component of velocity is maximum
  4. The acceleration is constant in both magnitude and direction Correct answer.

Explanation

In projectile motion, the only force is gravity, which gives a constant acceleration g directed vertically downwards. The horizontal component of velocity remains constant, while the vertical component changes uniformly.

Question 45Waves and Optics

A progressive wave is described by y = 0.04 sin 2π(50t − 2x), where y and x are in metres and t in seconds. What is the speed of the wave?

  1. 100 m/s
  2. 0.5 m/s
  3. 25 m/s Correct answer.
  4. 50 m/s

Explanation

Comparing with y = A sin 2π(ft − x/λ) gives f = 50 Hz and 1/λ = 2, so λ = 0.5 m. The wave speed is v = fλ = 50 × 0.5 = 25 m/s, so the wave travels 25 m each second.

Question 46Waves and Optics

Which property of a wave is determined solely by the source producing it and is unchanged when the wave passes from air into glass?

  1. Amplitude
  2. Speed
  3. Wavelength
  4. Frequency Correct answer.

Explanation

Frequency is set by the vibrating source and stays constant across a boundary because the number of oscillations per second cannot change at the interface. Wavelength and speed both alter when the medium changes.

Question 47Waves and Optics

In a ripple tank, straight water waves strike a straight barrier at 40° to the barrier surface. At what angle to the barrier is the reflected wave travelling?

  1. 40° Correct answer.
  2. 20°
  3. 50°
  4. 80°

Explanation

The angle of incidence is measured from the normal. The wave makes 40° with the barrier, so it makes 50° with the normal, and the reflected wave also makes 50° with the normal, which is 40° with the barrier. Reflection therefore leaves the angle to the surface unchanged.

Question 48Waves and Optics

Light of wavelength 600 nm in air enters a medium of refractive index 1.5. What is its wavelength inside the medium?

  1. 900 nm
  2. 300 nm
  3. 600 nm
  4. 400 nm Correct answer.

Explanation

The frequency is unchanged, so the wavelength falls in proportion to the speed: λ_medium = λ_air / n = 600/1.5 = 400 nm. A higher refractive index always means a shorter wavelength inside the medium.

Question 49Waves and Optics

A ray of light in glass of refractive index 1.5 strikes the glass–air boundary at 50° to the normal. Taking the critical angle as about 42°, what happens to the ray?

  1. It emerges into the air along the boundary
  2. It emerges into the air bent towards the normal
  3. It is refracted at exactly 90° to the normal into the air
  4. It is totally internally reflected back into the glass Correct answer.

Explanation

Total internal reflection occurs only when light travels from a denser to a less dense medium and the angle of incidence exceeds the critical angle. Since 50° is greater than the critical angle of about 42°, no light is refracted out and the ray is totally internally reflected.

Question 50Waves and Optics

A converging lens of focal length 20 cm forms a real image of an object placed 30 cm from the lens. What is the image distance?

  1. 12 cm
  2. 10 cm
  3. 50 cm
  4. 60 cm Correct answer.

Explanation

Using 1/f = 1/u + 1/v with f = 20 cm and u = 30 cm gives 1/v = 1/20 − 1/30 = 1/60, so v = 60 cm. The positive value confirms a real image on the far side of the lens.