General Physics I — 2024 Past Questions

Lagos State University PHY101: 61 questions.

Topics: Application of Newtonian Mechanics, Newton's Laws of Motion, Kinematics, Equations of Motion, Conservation of Linear Momentum, Circular Motion, Gravitation, Potential Energy, Torque, Impulse, Rotational Motion, Moments of Inertia, Work and Energy, Kinetic Energy and Work, Relative Motion, Newton's Law of Gravitation, Vectors and Scalars, Momentum Conservation

1. Which of the following is true?
   1. The limiting frictional force is found to increase when the block of wood is loaded with weights
   2. The value of the limiting frictional force is unchanged when a block of wood is turned on another side of different surface area
   3. The frictional force between two surfaces in relative motion always opposes the relative motion
   4. All of the above
2. If a stone of mass m is whirled round in a circle of radius r with a uniform speed v, then the centripetal force F is given by:
   1. mv²/r
   2. mv/r
   3. m²v/r
   4. mr/v²
3. A body starts from rest with an acceleration of 2 m s⁻². What velocity does it attain after 10 s?
   1. 20 m/s
   2. 10 m/s
   3. 15 m/s
   4. 12 m/s
4. A ball moving with an initial velocity of 5 m/s is accelerated uniformly at the rate of 4 m/s² for 15 s in the same direction as it is moving before. Calculate the distance covered by the ball during the period for which it is accelerated.
   1. 230 m
   2. 200 m
   3. 525 m
   4. 625 m
5. Which of the following is true for a velocity-time graph?
   1. The slope at a particular time gives the magnitude of the instantaneous acceleration at that time
   2. If the graph is a straight line, then the acceleration is uniform, else non-uniform
   3. The area under the graph is the displacement (distance covered)
   4. All of the above
6. A particle of mass m is given an impulse such that the velocity of the particle changes from v₁ to v₂. The impulse is equal to
   1. m(v₂ − v₁)
   2. m(v₂ + v₁)
   3. ½m(v₂² − v₁²)
   4. m(v₂ − v₁)/t
7. Which of the following statements is correct?
   1. A body cannot be accelerated by frictional force
   2. Frictional force is always present between any two surfaces in contact
   3. Kinetic friction is greater than rolling friction
   4. Frictional force is directly proportional to the area of contact between two surfaces
8. When a man stands on a spring balance, the reading is 75 kg. If the man jumps off the spring balance, what will be the final reading of the spring balance?
   1. Remains unchanged
   2. Increases
   3. Decreases at first then goes to zero
   4. Increases at first then goes to zero
9. For a body of constant mass to have a constant momentum, which of the following must be true?
   1. Its acceleration is zero
   2. The net force on it is zero
   3. Its velocity is constant
   4. All of the above
10. When two bodies stick together after collision, the collision is said to be
    1. Partially elastic collision
    2. Partially inelastic collision
    3. Totally elastic collision
    4. Totally inelastic collision
11. A body of mass m moving with a constant velocity v hits another body of the same mass moving with the same velocity but in the opposite direction and sticks to it. The velocity of the compound body after the collision is?
    1. Twice the initial velocity
    2. Half the initial velocity
    3. The same as the initial velocity
    4. Zero
12. A 50 g bullet moving with a velocity of 10 m/s strikes a block of mass 950 g at rest and gets embedded in it. The loss in kinetic energy will be?
    1. 2.375 J
    2. 0.95 J
    3. 0.05 J
    4. 0.5 J
13. When a force is exerted on a body, which of the following may change?
    1. Direction of motion
    2. Momentum
    3. Kinetic energy
    4. All of the above
14. Which of the following statements is correct?
    1. Rate of change of momentum corresponds to force
    2. Rate of change of momentum corresponds to kinetic energy
    3. All of the above
    4. None of the above
15. A stone is released from the window of a train moving along a horizontal straight track. As seen by an observer on the ground, the stone will hit the ground following a
    1. Hyperbolic path
    2. Straight path
    3. Circular path
    4. Parabolic path
16. The range of a projectile depends on
    1. The initial velocity and the angle of projection
    2. Only the angle of projection
    3. The mass of the projectile
    4. All of the above
17. What is the length of a train which crosses a bridge of 150 m in 20 s with a speed of 40 km/hr?
    1. 222 m
    2. 150 m
    3. 72.2 m
    4. 70.5 m
18. The velocity of a body of mass 20 kg decreases from 20 m/s to 5 m/s in a distance of 100 m. The force on the body is
    1. −27.5 N
    2. −47.5 N
    3. −37.5 N
    4. −67.5 N
19. A ball of mass 0.2 kg is thrown vertically upwards by applying a force by hand. If the hand moves 0.2 m while applying the force and the ball goes up to 2 m height further, find the magnitude of the force. (Take g = 10 m s⁻²)
    1. 16 N
    2. 20 N
    3. 22 N
    4. 10 N
20. The same force acts on two bodies of different masses 2 kg and 4 kg, initially at rest. The ratio of the times required to acquire the same final velocity is
    1. 1 : 2
    2. 2 : 1
    3. 1 : 4
    4. 4 : 1
21. A 0.5 kg ball moving with a speed of 12 m/s strikes a hard wall at an angle of 30° with the wall. It is reflected with the same speed and at the same angle. If the ball is in contact with the wall for 0.25 s, the average force acting on the wall is
    1. 96 N
    2. 48 N
    3. 24 N
    4. 12 N
22. Two forces F_A and F_B are 6 N at 36° to the positive x-axis and 7 N along the negative x-axis respectively. Find the magnitude of the resultant F_A + F_B.
    1. 2.14 N
    2. 4.13 N
    3. 12.36 N
    4. 2.95 N
23. Suppose you want to place a 1000 kg weather satellite into a circular orbit 300 km above the surface of the Earth of radius 6380 km. What speed must it have? (Take M_E = 5.97 × 10²⁴ kg, G = 6.67 × 10⁻¹¹ N m² kg⁻²)
    1. 3440 m s⁻¹
    2. 5920 m s⁻¹
    3. 7720 m s⁻¹
    4. 8920 m s⁻¹
24. A wheel accelerates so that its angular speed increases uniformly from 150 to 580 rad s⁻¹ with an angular displacement of 100.53 rad. Calculate its angular acceleration.
    1. 320 rad s⁻²
    2. 1320 rad s⁻²
    3. 1561 rad s⁻²
    4. 1650 rad s⁻²
25. Find the apparent weight of a person whose mass is 60 kg in an elevator, when the elevator is stationary. (Take g = 9.8 m s⁻²)
    1. 588 N
    2. 708 N
    3. 60 N
    4. 51 N
26. A car accelerates uniformly from rest to 36 km h⁻¹ in 4 s. Calculate the magnitude of the acceleration and the distance covered during this 4 s interval.
    1. 2.5 m s⁻², 20 m
    2. 1.5 m s⁻², 12 m
    3. 1.0 m s⁻², 5 m
    4. 0.5 m s⁻², 2.5 m
27. A car started from rest and moved with an acceleration of 2 m s⁻² until its engine was turned off after 3 s. The car then decelerated for 10 s at 0.25 m s⁻² before the brakes were applied, after which it came to rest 3 s later. Calculate the total distance through which the car moved.
    1. 80.75 m
    2. 61.75 m
    3. 50.75 m
    4. 30.75 m
28. A body slides down a smooth inclined plane of angle 30° to the horizontal. Find the distance covered after 15 s from rest. (Take g = 9.8 m s⁻²)
    1. 80.2 m
    2. 490.4 m
    3. 551.3 m
    4. 600.5 m
29. Find the minimum velocity with which a missile can be projected from a military base to hit a target 500 km away, assuming only gravitational force. (Take g = 9.8 m s⁻²)
    1. 3210.5 m s⁻¹
    2. 2213.6 m s⁻¹
    3. 2010.5 m s⁻¹
    4. 1210.6 m s⁻¹
30. A car of mass 1380 kg is moving due east with an initial speed of 27 m s⁻¹. After 8 s, the car has slowed down to 17 m s⁻¹. Find the net force that produces the deceleration.
    1. −1.25 × 10³ N
    2. −1.45 × 10³ N
    3. −1.73 × 10³ N
    4. −1.93 × 10³ N
31. A uniform rod 1 m long and weighing 30 N is supported in a horizontal position on a pivot with weights of 40 N and 50 N suspended from its ends. Calculate the position of the pivot from the 50 N weight.
    1. 0.54 m
    2. 0.46 m
    3. 0.44 m
    4. 0.36 m
32. Determine the acceleration due to gravity for a satellite in orbit 200 km above the surface of the Earth. (Take g = 9.8 m s⁻², G = 6.67 × 10⁻¹¹ N m² kg⁻², M_E = 5.98 × 10²⁴ kg, R_E = 6.38 × 10⁶ m)
    1. 9.8 m s⁻²
    2. 9.5 m s⁻²
    3. 9.2 m s⁻²
    4. 8.8 m s⁻²
33. Mass is to translational motion as ______ is to rigid body rotational motion.
    1. Weight
    2. Moment of inertia
    3. Torque
    4. Angular momentum
34. A particle of mass 1 kg oscillates with simple harmonic motion along a line. At what location during the motion is its potential energy maximum?
    1. At the highest end
    2. At the lowest end
    3. At the two extreme positions
    4. Midway between the extreme positions
35. A satellite is said to be parked when
    1. It has the same period of revolution as the Earth
    2. It has the same radius as the Earth
    3. It is static
    4. It moves with constant velocity
36. A particle in SHM has a period of 0.45 s. If the maximum speed attained during the motion is 0.3 m/s, what is the amplitude of the motion?
    1. 0.0215 m
    2. 2.15 m
    3. 0.215 m
    4. 0.00215 m
37. A particle moves in a circle of radius 0.5 m. At time t seconds, its angular velocity is π(10 − 2t) rad/s. Find its speed and acceleration after 4 s.
    1. 3.14 m/s and 20.0 m/s²
    2. 6.28 m/s and 20.0 m/s²
    3. 3.14 m/s and 9.87 m/s²
    4. 1.57 m/s and 4.93 m/s²
38. Compute the moment of inertia of a uniform rod of length 5 m about an axis through its midpoint, if the mass of the rod is 2 kg.
    1. 417 kg m²
    2. 41.7 kg m²
    3. 4.17 kg m²
    4. 0.417 kg m²
39. Find the work done when a trunk is dragged a distance of 10 m by a force of 50 N applied at 45° to the horizontal.
    1. 249 J
    2. 354 J
    3. 474 J
    4. 549 J
40. Calculate the power developed by an 80 kg student who, in 10 seconds, runs up stairs that have a vertical height of 5.0 m. (Take g = 9.8 m s⁻²)
    1. 3920 W
    2. 392 W
    3. 39.2 W
    4. 3.92 W
41. A particle travels with constant speed around a circle of radius r in a time T. Express the particle's centripetal acceleration a in terms of r and T.
    1. 4π²r/T²
    2. 2πr/T²
    3. 4πr²/T
    4. π²r/T²
42. A cone standing on its apex is an example of
    1. Stable equilibrium
    2. Unstable equilibrium
    3. Neutral equilibrium
    4. Balanced equilibrium
43. A 1000 kg car accelerates uniformly from rest to a speed of 30 m/s. Calculate the kinetic energy gained.
    1. 4.5 × 10⁵ J
    2. 3.5 × 10⁵ J
    3. 2.5 × 10⁵ J
    4. 1.5 × 10⁵ J
44. The Earth's mass is approximately 80 times as large as the Moon's mass, and the Moon's orbit radius is approximately 3.8 × 10⁵ km. Calculate the gravitational force of attraction between the two. (Take M_E = 5.98 × 10²⁴ kg, G = 6.67 × 10⁻¹¹ N m² kg⁻²)
    1. 2.1 × 10²⁰ N
    2. 2.4 × 10²⁰ N
    3. 2.5 × 10²⁰ N
    4. 3.5 × 10²⁰ N
45. The following are examples of a simple harmonic oscillator when given a slight displacement, except
    1. A mass at the centre of a string under constant tension
    2. A fixed length of non-viscous liquid in a U-tube of constant cross-section
    3. A rotating rigid body
    4. A hydrometer of mass m in a liquid of density ρ
46. A mass of 80 kg slides down a smooth inclined plane 16 m high and 80 m long. Neglecting friction, calculate the potential energy of the mass at the top of the slope. (Take g = 9.8 m s⁻²)
    1. 1.25 × 10⁴ J
    2. 2.5 × 10⁴ J
    3. 4.5 × 10⁴ J
    4. 5.0 × 10⁴ J
47. When the sum of all the forces acting on a block on an inclined plane is zero, the block
    1. Must be at rest
    2. Must be accelerating
    3. May be slowing down
    4. May be moving at a constant speed
48. A skier is going down a slope at constant speed. The coefficient of friction between the skier and the incline is 0.61. Find the angle of inclination.
    1. 52°
    2. 38°
    3. 31°
    4. 20°
49. A box weighing 46 newtons rests on an inclined plane that makes an angle of 25° with the horizontal. What is the magnitude of the component of the box's weight perpendicular to the incline?
    1. 19 N
    2. 21 N
    3. 26 N
    4. 42 N
50. An 8.0-newton block is accelerating down a frictionless ramp inclined at 15° to the horizontal. What is the magnitude of the net force causing the block's acceleration?
    1. 0 N
    2. 2.1 N
    3. 7.7 N
    4. 9.8 N
51. Water flows between two plates, of which the upper one is stationary and the lower one is moving with a velocity V. What will be the velocity of the fluid in contact with the upper plate?
    1. V
    2. V/2
    3. 2V
    4. 0
52. What is the magnitude of the force required to stretch a 20 cm-long spring, with a spring constant of 100 N/m, to a length of 21 cm?
    1. 1.0 N
    2. 1.01 N
    3. 0.10 N
    4. 1.10 N
53. A 2.0 m-long wire stretches 1.0 mm when subjected to a load. What is the tensile strain in the wire?
    1. 0.0005
    2. 0.005
    3. 0.05
    4. 0.5
54. The only elastic modulus that applies to fluids is
    1. Young's modulus
    2. Shear modulus
    3. Modulus of rigidity
    4. Bulk modulus
55. Young's modulus of the material of a rope is defined as
    1. Tensile stress × tensile strain
    2. Tensile stress ÷ tensile strain
    3. Tensile strain ÷ tensile stress
    4. Force ÷ extension
56. According to the principle of buoyancy (Archimedes' principle), a body totally or partially immersed in a fluid will be lifted up by a force equal to
    1. The weight of the body
    2. More than the weight of the body
    3. Less than the weight of the body
    4. The weight of the fluid displaced by the body
57. A hydraulic ram is a device used to
    1. Store the energy of water
    2. Increase the pressure of water
    3. Lift water from deep wells
    4. Lift a small quantity of water to a greater height when a large quantity of water is available at a small height
58. Water is flowing through a non-uniform cross-sectional pipe. Where the radius of the pipe is 2 cm, the velocity of water is 20 cm/s. At another place, where the radius of the pipe is 6 cm, find the velocity of the water.
    1. 2.22 cm/s
    2. 2.22 m/s
    3. 22.2 cm/s
    4. 22.2 m/s
59. A flow in which the quantity of liquid flowing per second is constant is called ______ flow.
    1. Steady
    2. Streamline
    3. Unsteady
    4. Turbulent
60. The absolute pressure at a depth h below the surface of a liquid of density ρ is
    1. Greater than the atmospheric pressure by ρgh
    2. Less than the atmospheric pressure by ρgh
    3. Equal to the atmospheric pressure
    4. Decreases and then increases with depth
61. When the temperature is increased, the angle of contact of a liquid
    1. Increases
    2. Decreases
    3. Remains the same
    4. First increases and then decreases

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