FSc Pre-Medical Physics: Force & Motion MCQs

FSc Pre-Medical Physics: Force & Motion MCQs — sample questions

1. Question 1

   Q1. A 5 kg block accelerates at 3 m/s² when a force is applied. What is the magnitude of the force?

   • A) 15 N
   • B) 3 N
   • C) 5 N
   • D) 8 N

   Answer: 15 N

   Explanation: F = ma = 5 kg × 3 m/s² = 15 N. Option B confuses force with acceleration.

2. Question 2

   Q2. Which force opposes the relative motion of two surfaces in contact?

   • A) Gravitational force
   • B) Frictional force
   • C) Normal force
   • D) Tension force

   Answer: Frictional force

   Explanation: Friction opposes relative motion. Gravitational force acts downward (option A).

3. Question 3

   Q3. A car accelerates from rest. What is the direction of the net force on the car?

   • A) Opposite to the car's motion
   • B) Same as the car's velocity
   • C) Same as the car's acceleration
   • D) Perpendicular to the car's motion

   Answer: Same as the car's acceleration

   Explanation: Net force direction equals acceleration direction (Newton’s Second Law). Option B confuses velocity with acceleration.

4. Question 4

   Q4. Which quantity remains constant during projectile motion?

   • A) Vertical velocity
   • B) Horizontal velocity
   • C) Kinetic energy
   • D) Acceleration

   Answer: Horizontal velocity

   Explanation: Horizontal velocity is constant (no air resistance). Acceleration is downward (option D is incorrect).

5. Question 5

   Q5. What is the SI unit of impulse?

   • A) Newton-second
   • B) Joule
   • C) Watt
   • D) Pascal

   Answer: Newton-second

   Explanation: Impulse = F×t, measured in N·s. Joule (B) is energy’s unit.

6. Question 6

   Q6. A 2 kg object moving at 4 m/s collides and sticks to a 3 kg object at rest. What is their combined velocity?

   • A) 1.6 m/s
   • B) 2.0 m/s
   • C) 4.0 m/s
   • D) 3.0 m/s

   Answer: 1.6 m/s

   Explanation: Conservation of momentum: (2×4) = (5)v → v=1.6 m/s. Option B ignores the combined mass.

7. Question 7

   Q7. Which factor does NOT affect the maximum speed of a car on a banked road?

   • A) Radius of curvature
   • B) Angle of banking
   • C) Mass of the car
   • D) Friction coefficient

   Answer: Mass of the car

   Explanation: Mass cancels in equations for banked curves. Option D affects friction-dependent scenarios.

8. Question 8

   Q8. What is the acceleration of an object in uniform circular motion?

   • A) Zero
   • B) Constant magnitude, changing direction
   • C) Constant in direction
   • D) Dependent on tangential velocity

   Answer: Constant magnitude, changing direction

   Explanation: Centripetal acceleration changes direction but magnitude is constant. Option A ignores acceleration.

9. Question 9

   Q9. A force of 10 N acts on a 5 kg object for 2 seconds. What is the change in momentum?

   • A) 20 kg·m/s
   • B) 5 kg·m/s
   • C) 10 kg·m/s
   • D) 2 kg·m/s

   Answer: 20 kg·m/s

   Explanation: Impulse = F×t = 10 N × 2 s = 20 kg·m/s. Option C ignores time duration.

10. Question 10

    Q10. A ball is thrown vertically upward. What is its acceleration at the highest point?

    • A) 0 m/s²
    • B) 9.8 m/s² downward
    • C) 9.8 m/s² upward
    • D) Depends on initial velocity

    Answer: 9.8 m/s² downward

    Explanation: Gravity always acts downward at 9.8 m/s². Option A ignores gravity.

11. Question 11

    Q11. Which law explains why a passenger leans outward in a turning car?

    • A) Newton’s First Law
    • B) Newton’s Second Law
    • C) Newton’s Third Law
    • D) Law of Conservation of Momentum

    Answer: Newton’s First Law

    Explanation: Inertia (First Law) causes the lean. Option C refers to action-reaction pairs.

12. Question 12

    Q12. What is the work done by the centripetal force in circular motion?

    • A) Zero
    • B) Equal to kinetic energy
    • C) Equal to potential energy
    • D) Dependent on radius

    Answer: Zero

    Explanation: Centripetal force is perpendicular to motion (no work done). Option B confuses energy types.

13. Question 13

    Q13. Which of these is a vector quantity?

    • A) Speed
    • B) Force
    • C) Mass
    • D) Time

    Answer: Force

    Explanation: Force has direction (vector). Speed (A) is scalar.

14. Question 14

    Q14. A 10 N force pulls a 2 kg block on a frictionless surface. What is the acceleration?

    • A) 5 m/s²
    • B) 2 m/s²
    • C) 10 m/s²
    • D) 0 m/s²

    Answer: 5 m/s²

    Explanation: a = F/m = 10 N / 2 kg = 5 m/s². Option C uses force instead of acceleration.

15. Question 15

    Q15. What is the relationship between static and kinetic friction coefficients?

    • A) μ_s > μ_k
    • B) μ_s = μ_k
    • C) μ_s < μ_k
    • D) μ_s is independent of μ_k

    Answer: μ_s > μ_k

    Explanation: Static friction is higher than kinetic. Option C reverses the inequality.

16. Question 16

    Q16. A 500 kg satellite orbits Earth. What is the direction of Earth’s gravitational force on it?

    • A) Toward Earth’s center
    • B) Away from Earth’s center
    • C) Along orbital motion
    • D) Perpendicular to orbit

    Answer: Toward Earth’s center

    Explanation: Gravity acts as a centripetal force toward Earth’s center. Option C refers to motion direction.

17. Question 17

    Q17. If two forces of 6 N and 8 N act perpendicularly, their resultant is:

    • A) 10 N
    • B) 14 N
    • C) 2 N
    • D) 7 N

    Answer: 10 N

    Explanation: Resultant = √(6² + 8²) = 10 N. Option B adds vectors directly.

18. Question 18

    Q18. What is the acceleration of a free-falling object near Earth’s surface?

    • A) 9.8 m/s²
    • B) 4.9 m/s²
    • C) 0 m/s²
    • D) Depends on mass

    Answer: 9.8 m/s²

    Explanation: Gravity causes 9.8 m/s² acceleration. Option D is incorrect as mass cancels.

19. Question 19

    Q19. Which statement about action-reaction pairs is true?

    • A) They act on the same object
    • B) They are equal in magnitude, opposite in direction
    • C) They cancel each other
    • D) They are of different types

    Answer: They are equal in magnitude, opposite in direction

    Explanation: Newton’s Third Law defines action-reaction pairs. Option A confuses single-object forces.

20. Question 20

    Q20. A 2 kg object is accelerated from 3 m/s to 7 m/s in 2 seconds. What is the applied force?

    • A) 4 N
    • B) 5 N
    • C) 2 N
    • D) 10 N

    Answer: 4 N

    Explanation: F = mΔv/Δt = 2 kg × (4/2) = 4 N. Option B adds velocities directly.