General Physics I — 2020 Past Questions

University of Ilorin PHY101: 56 questions.

Topics: Conservation Principles in Physics, Kinematics, Rotational motion, Units and Dimension, Newton's Law of Motion, Application of Newtonian Mechanics, Circular motion, System of particles, Center of mass

1. A body with initial velocity 135 m/s was projected at an angle 45°. What is the time taken to reach the maximum height?
   1. 7.8 s
   2. 9.74 s
   3. 9.81 s
   4. 6.78 s
2. Which of these cannot be a unit of impulse?
   1. Js/m
   2. Nm⁻¹
   3. Ns
   4. kg·m·s⁻¹
3. If a body of mass 12.2 kg with initial speed 15.0 m/s collides with another body of mass 2.2 kg moving at 28.4 m/s in the same direction, find the kinetic energy transferred in this inelastic collision.
   1. 180 J
   2. 169 J
   3. 167 J
   4. 160 J
4. For a pendulum at equilibrium (Q) and maximum displacement (P & R), which statement is not true?
   1. No potential energy at Q
   2. Maximum P.E at P and R
   3. Maximum P.E at Q
   4. Maximum K.E at Q
5. If two masses (1g and 4g) have the same kinetic energy, calculate the ratio of their linear momentum.
   1. 1:16
   2. 1:4
   3. 1:2
   4. 1:8
6. Angular position is the
   1. Angle of reference relative to a dynamic direction
   2. Angle of reference relative to a direction
   3. Angle of reference relative to a fixed direction
   4. All options are correct
7. A particle undergoes a change in position from P₁ to P₂. This is called
   1. Angular displacement
   2. Angular acceleration
   3. Distance
   4. Velocity
8. If the inertia of a body is given as I = (Ma²/2), what is the radius of gyration?
   1. (a²/2)^(1/2)
   2. a²/2
   3. a/2
   4. a/4
9. Which of these is true for two objects undergoing elastic collision? I. KEᵢ = KE_f II. Total momentum is conserved III. The objects bounce off with different velocities
   1. I & II
   2. I & III
   3. II & III
   4. All of the above
10. Dimensions help to...
    1. Reform equations
    2. Derive equations
    3. All of the above
    4. None of the above
11. The formula for maximum height in projectile motion is
    1. 2u sinα/g
    2. u² sin²α/g
    3. 2u sinα/g
    4. u² sin²α/2g
12. Convert 0.25 rev to degrees
    1. 13.25°
    2. 14.33°
    3. 12.47°
    4. 90°
13. The period of a string is 2 s. If the length is doubled, what is the new period?
    1. 1.41 s
    2. 2.83 s
    3. 2.00 s
    4. 4.00 s
14. Which of the following is correct about inelastic collision? I. KE before = KE after II. Objects move with common velocity III. Momentum is conserved IV. Objects move at different velocities
    1. I & II
    2. I & III
    3. IV & III
    4. II & III
15. Find the acceleration of a body with initial velocity u = -3.2i + 6.0j and final velocity v = 2.9i - 4.1j in 5 s.
    1. 0.68 m/s²
    2. 0.94 m/s²
    3. 2.36 m/s²
    4. 2.56 m/s²
16. What is the potential energy at point r for a force F = -k/r²?
    1. k/r
    2. -k/r
    3. k/r²
    4. -k/r²
17. A body moves in a circular path with velocity 0.88 m/s and radius 0.02 m. Calculate the frequency.
    1. 44 Hz
    2. 7 Hz
    3. 5 Hz
    4. 22 Hz
18. A body changes velocity from 15 m/s to 45 m/s in 5 s. Calculate the acceleration.
    1. 15 m/s²
    2. 45 m/s²
    3. 6 m/s²
    4. 5 m/s²
19. A person lifts a 20 N mass through 10 m with 40% efficiency. Calculate work lost to friction.
    1. 200 J
    2. 120 J
    3. 80 J
    4. 280 J
20. A 50 g body is dropped from a ceiling and reaches the ground in 1 s. Calculate its maximum potential energy at the ceiling.
    1. 0 J
    2. 256 J
    3. 28 J
    4. 15 J
21. Which of the following is not a natural force?
    1. Radioactive force
    2. Force between nucleus and electron
    3. Centripetal and centrifugal force
    4. Gravitational force
22. Which of these has the dimension [MLT]?
    1. Work
    2. Pressure
    3. Power
    4. None
23. A force of 25 N drags an object 10 m with 7 N friction. Calculate the resultant work done.
    1. 180 J
    2. 250 J
    3. 70 J
    4. 36 J
24. Calculate the coefficient of friction if force is 140 N and mass is 60 kg.
    1. 0.24
    2. 0.14
    3. 0.30
    4. 0.36
25. A 50 g mass swings with a period of 1.7 s. Calculate the force constant.
    1. 0.88 N/m
    2. 0.68 N/m
    3. 0.56 N/m
    4. 0.78 N/m
26. What is the time taken for an object starting from rest to reach 60 m/s at 14 m/s²?
    1. 3.29 s
    2. 4.26 s
    3. 4.29 s
    4. 3.33 s
27. The tension in a wire of length 0.6 m is 1.5 N. Calculate the tension for length 0.4 m.
    1. 3.38 N
    2. 4.38 N
    3. 2.36 N
    4. 1.38 N
28. Which of the following is not a derived unit?
    1. Steradian
    2. Radian
    3. Ampere
    4. Tesla
29. The force acting opposite the center of rotation in circular motion is called
    1. Centripetal force
    2. Centrifugal force
    3. Tension
    4. Gravitational force
30. A 25 kg mass moving at 12 m/s splits into m₁ = 20 kg (v₁ = 10 m/s) and m₂ = 5 kg. Find v₂.
    1. 20 m/s
    2. 15 m/s
    3. 12 m/s
    4. 10 m/s
31. A projectile is launched at speed V₀ and angle α. What is the time of flight?
    1. T = 2V₀ sinα/g
    2. T = V₀² sinα/2g
    3. T = V₀² sinα/g
    4. T = V₀ sin2α/g
32. A 50 g mass oscillates with amplitude 12 cm and ω = 3.986 rad/s. Calculate maximum velocity.
    1. 0.48 m/s
    2. 0.12 m/s
    3. 0.38 m/s
    4. 0.26 m/s
33. A 0.02 kg mass is thrown horizontally from a 40 m cliff. What is its KE at impact?
    1. 7.74 J
    2. 7.84 J
    3. 7.66 J
    4. 7.60 J
34. What happens in elastic collision? I. Momentum conserved II. KE conserved III. Momentum increased IV. KE increased
    1. I & II
    2. I & III
    3. I, II & IV
    4. All of the above
35. The unit of pressure is
    1. kg·m·s²
    2. N·m
    3. N·s
    4. N/m²
36. A body of radius 30cm moved with a velocity of 15m/s during 8s. What is the angular acceleration?
    1. 1.88 rad/s²
    2. 6.25 rad/s²
    3. 2.36 rad/s²
    4. 7.36 rad/s²
37. If a body of mass 12.5g with initial velocity 10m/s and final velocity of 22.2m/s. Calculate the work done.
    1. 2.46 J
    2. 3.45 J
    3. 1.45 J
    4. 2.67 J
38. A mass of 15.2kg has a velocity of 12m/s and collides with a mass of 12.2kg and velocity of 20m/s. If they move in the same direction and the collision is inelastic, calculate the energy lost as heat or sound.
    1. 217 J
    2. 225 J
    3. 210 J
    4. 180 J
39. A body undergoing rotational motion from rest has an acceleration of 3.18 rad/s² in 8s. Calculate the revolution in rad?
    1. 101.76 rad
    2. 203.52 rad
    3. 50.88 rad
    4. 25.44 rad
40. A body of mass 400g was extended by a length of 35cm. Calculate the Spring Constant (Take g=9.8 m/s²).
    1. 11.2 N/m
    2. 10.7 N/m
    3. 5.6 N/m
    4. 8.8 N/m
41. Which of the following is correct about moment of inertia and mass? i. Moment of inertia is for a rotational rigid body while mass is for translational motion. ii. Unit of inertia is kg·m² while mass is kg. iii. Inertia is constant while mass varies.
    1. All are correct
    2. i and ii
    3. i and iii
    4. ii and iii
42. For the period of pendulum bob given by T = mˣlʸgᶻ, find the values of x, y, and z.
    1. 0, ½, -½
    2. ½, 0, ½
    3. 0, 0, ½
    4. ½, -½, ½
43. A body thrown with an initial velocity 135 m/s at an angle of 45°. Calculate the maximum height attained.
    1. 464.9 m
    2. 135.6 m
    3. 67.5 m
    4. 270 m
44. A fan rotates at an angular frequency of 900 rpm. If the distance from the center to the end of the arm of a blade is 20 cm, calculate its tangential velocity.
    1. 18.85 m/s
    2. 171.89 m/s
    3. 180.00 m/s
    4. 30.00 m/s
45. What is the unit of energy?
    1. metre
    2. Joules
    3. kilogram
    4. Watt
46. What is the definition of moment of inertia?
    1. The sum of the product of each of the particles and the square of the perpendicular distance to the axis of rotation
    2. The product of mass of a body and its acceleration
    3. The product of mass of a body and its velocity
    4. The work done by a body per unit time
47. A bicycle wheel has a diameter of 0.05 m, a mass of 0.80 kg, and a moment of inertia about its axle of 4.0 × 10⁻² kg·m². Determine the total kinetic energy of the wheel.
    1. 87 J
    2. 78 J
    3. 39 J
    4. 48 J
48. How long will it take a 60 kg man to climb a height of 22 m if he has expended energy at the rate of 0.25 kW?
    1. 5.3 s
    2. 34.5 s
    3. 41.6 s
    4. 52.8 s
49. The velocity of the motion of a given particle is represented by equation: V = 10 cm/s + (2 cm/s³)t². Find the change in the velocity of the particle in the time interval of t₁ = 2s and t₂ = 5s.
    1. 54 cm/s
    2. 40 cm/s
    3. 24 cm/s
    4. 42 cm/s
50. A question on (something) at the verge of sliding.
    1. Coefficient of static friction
    2. Coefficient of kinetic friction
    3. Frictional motion
    4. Frictional force
51. A question about the forces acting on a body before/when it attains terminal velocity.
    1. Gravitational pull, viscous drag
    2. Viscous drag, tension, weight
    3. Only gravitational pull
    4. Only viscous drag
52. Which is true for center of mass? I. At the geometric centre II. No external force acts on it III. It is the point where mass is concentrated.
    1. I & III
    2. I & II
    3. II & III
    4. I only
53. A ball is dropped from a building 80 m high. What's the velocity of the ball when it reaches the middle point of the building? (g = 10 m/s²).
    1. 28.28 m/s
    2. 40 m/s
    3. 20 m/s
    4. 56.57 m/s
54. The total kinetic energy of a rotating body is given by:
    1. ½mv²
    2. ½mv² + ½Iω²
    3. Only ½Iω²
    4. mgh + ½mv²
55. A crate of mass 50 kg on a frictionless horizontal floor is dragged at an angle of 46° with a force of 35 N. Calculate work done.
    1. 875 J
    2. 760 J
    3. 945 J
    4. 1020 J
56. A spring of mass 50 g was stretched to a certain length. After a 20 g mass was added to it, it stretches 7 cm extra. Calculate the elastic constant of the spring.
    1. 2.8 N/m
    2. 5.6 N/m
    3. 11.2 N/m
    4. 1.4 N/m

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