Force and Motion

28 free MDCAT Physics MCQs on Force and Motion (PM&DC syllabus), each with the answer, an explanation and the textbook line it comes from. Tap to check, no sign-up.

Tap an answer to check it · 28 questions

1. Question 1

   A body whose velocity changes by equal amounts in equal intervals of time has:
   • AUniform acceleration
   • BVariable acceleration
   • CUniform velocity
   • DZero acceleration
   Show answer and explanation

   Answer: A) Uniform acceleration

   Then average and instantaneous accelerations are equal. Source: PHYSICS 11 KPK (taleem360.com), p. 80.

2. Question 2

   The branch of mechanics that studies motion without considering its causes is:
   • ADynamics
   • BKinematics
   • CStatics
   • DThermodynamics
   Show answer and explanation

   Answer: B) Kinematics

   Dynamics deals with the forces that cause motion. Source: 11 Physics Book FBISE, p. 33.

3. Question 3

   Newtonian mechanics is taken as valid for speeds less than about:
   • A1% of light speed
   • B10% of light speed
   • C50% of light speed
   • D100% of light speed
   Show answer and explanation

   Answer: A) 1% of light speed

   About 3000 km/s; faster than this, relativity is needed. Source: PHYSICS 11 KPK (taleem360.com), p. 92.

4. Question 4

   A 46 g tennis ball is fired from a 1.35 kg cannon, which recoils at 2.1 m/s. The muzzle speed of the ball is about:
   • A1.4 m/s
   • B2.1 m/s
   • C29.3 m/s
   • D60.9 m/s
   Show answer and explanation

   Answer: D) 60.9 m/s

   Total momentum stays zero: 1.35 x 2.1 = 0.046 v, v = 2.8/0.046 = 60.87 m/s. Source: 11 Physics Book FBISE, p. 46.

5. Question 5

   A bat gives a cricket ball an impulse of 13.6 N s in 1.6 ms. The average force on the ball is:
   • A850 N
   • B13.6 N
   • C8500 N
   • D2176 N
   Show answer and explanation

   Answer: C) 8500 N

   F = J/t = 13.6/0.0016 = 8500 N. Source: PHYSICS 11 KPK (taleem360.com), p. 96.

6. Question 6

   Taking g = 10 m/s2, a freely falling object covers in its 2nd second a distance of:
   • A25 m
   • B20 m
   • C5 m
   • D15 m
   Show answer and explanation

   Answer: D) 15 m

   S(2 s) - S(1 s) = 20 - 5 = 15 m; in the 3rd second it covers 25 m. Source: PHYSICS 11 KPK (taleem360.com), p. 115.

7. Question 7

   The time rate of change of momentum gives:
   • AImpulse
   • BForce
   • CAcceleration
   • DPower
   Show answer and explanation

   Answer: B) Force

   Newton's second law: F = delta p / delta t. Source: PHYSICS 11 KPK (taleem360.com), p. 94.

8. Question 8

   The slope of a displacement-time graph gives the:
   • AMomentum
   • BAcceleration
   • CDistance
   • DVelocity
   Show answer and explanation

   Answer: D) Velocity

   It can be negative, indicating reverse motion; the slope of distance-time gives speed. Source: PHYSICS 11 KPK (taleem360.com), p. 81.

9. Question 9

   A horizontal line on a displacement-time graph means the body:
   • AIs at rest
   • BMoves uniformly
   • CIs accelerating
   • DMoves backward
   Show answer and explanation

   Answer: A) Is at rest

   Time passes with no change in displacement, so velocity is zero. Source: PHYSICS 11 KPK (taleem360.com), p. 82.

10. Question 10

    A car moving in the negative x-direction is speeding up. Its acceleration is:
    • ANegative
    • BPositive
    • CZero
    • DUndefined
    Show answer and explanation

    Answer: A) Negative

    Negative acceleration is not simply deceleration; the sign depends on the chosen positive direction. Source: PHYSICS 11 KPK (taleem360.com), p. 81.

11. Question 11

    When a body is decelerating, its velocity and acceleration point in:
    • AThe same direction
    • BOpposite directions
    • CPerpendicular directions
    • DRandom directions
    Show answer and explanation

    Answer: B) Opposite directions

    The magnitude of velocity is decreasing. Source: PHYSICS 11 KPK (taleem360.com), p. 80.

12. Question 12

    The three equations of motion apply only when acceleration is:
    • AConstant
    • BIncreasing
    • CDecreasing
    • DVariable
    Show answer and explanation

    Answer: A) Constant

    Motion is also taken along a straight line. Source: 11 Physics Book FBISE, p. 33.

13. Question 13

    In ideal projectile motion, the horizontal component of acceleration is:
    • A19.6 m/s2
    • B9.8 m/s2
    • C4.9 m/s2
    • D0 m/s2
    Show answer and explanation

    Answer: D) 0 m/s2

    The vertical component is g = 9.8 m/s2. Source: PHYSICS 11 KPK (taleem360.com), p. 104.

14. Question 14

    At the highest point of a projectile's path, the vertical component of velocity is:
    • AMaximum
    • BZero
    • CEqual to g
    • DEqual to the launch speed
    Show answer and explanation

    Answer: B) Zero

    The body momentarily stops rising; the horizontal component is unchanged. Source: PHYSICS 11 KPK (taleem360.com), p. 105.

15. Question 15

    Air resistance affects a projectile by:
    • AHaving no effect at all
    • BIncreasing range and height
    • CReducing its range and height
    • DIncreasing only its range
    Show answer and explanation

    Answer: C) Reducing its range and height

    Both velocity components decrease. Source: 11 Physics Book FBISE, p. 42.

16. Question 16

    For a projectile landing at its launch level, the time to reach the highest point is:
    • AA quarter of it
    • BEqual to the time of flight
    • CTwice the time of flight
    • DHalf the time of flight
    Show answer and explanation

    Answer: D) Half the time of flight

    T' = v sin theta / g, T = 2 v sin theta / g. Source: PHYSICS 11 KPK (taleem360.com), p. 107.

17. Question 17

    When object A exerts a force on object B, B exerts on A a force that is:
    • ASmaller, opposite
    • BEqual, same direction
    • CEqual and opposite
    • DLarger, opposite
    Show answer and explanation

    Answer: C) Equal and opposite

    Newton's third law: the forces act on different bodies. Source: PHYSICS 11 KPK (taleem360.com), p. 91.

18. Question 18

    Linear momentum is the product of:
    • AForce and velocity
    • BMass and acceleration
    • CForce and time
    • DMass and velocity
    Show answer and explanation

    Answer: D) Mass and velocity

    It points in the direction of velocity; unit kg m/s. Source: PHYSICS 11 KPK (taleem360.com), p. 111.

19. Question 19

    Impulse acting on a body is equal to its:
    • AChange in momentum
    • BRate of change of momentum
    • CChange in kinetic energy
    • DMass times acceleration
    Show answer and explanation

    Answer: A) Change in momentum

    J = F t = delta p; the rate of change of momentum is force. Source: PHYSICS 11 KPK (taleem360.com), p. 95.

20. Question 20

    A system is said to be isolated if:
    • ANet internal force is zero
    • BNet external force is zero
    • CIt has no momentum
    • DIts particles are at rest
    Show answer and explanation

    Answer: B) Net external force is zero

    Then the total momentum of the system is conserved. Source: 11 Physics Book FBISE, p. 44.

21. Question 21

    A bomb at rest explodes into two fragments of equal mass. The fragments move:
    • AOpposite, with unequal speeds
    • BSame way, with equal speeds
    • COpposite, with equal speeds
    • DAt right angles
    Show answer and explanation

    Answer: C) Opposite, with equal speeds

    Total momentum must remain zero. Source: 11 Physics Book FBISE, p. 45.

22. Question 22

    A cannon recoils much more slowly than the ball it fires because the cannon has:
    • AA greater force
    • BLess momentum
    • CZero momentum
    • DA heavy mass
    Show answer and explanation

    Answer: D) A heavy mass

    Both have equal and opposite momentum. Source: 11 Physics Book FBISE, p. 45.

23. Question 23

    Rockets and jet engines work on the principle of:
    • AConservation of momentum
    • BConservation of mass
    • CNewton's first law
    • DArchimedes' principle
    Show answer and explanation

    Answer: A) Conservation of momentum

    Hot gases rush out with large momentum; the machine gains equal and opposite momentum. Source: 11 Physics Book FBISE, p. 45.

24. Question 24

    For a perfectly elastic collision, the relative speed of approach is:
    • AGreater than that of separation
    • BEqual to that of separation
    • CLess than that of separation
    • DAlways zero after impact
    Show answer and explanation

    Answer: B) Equal to that of separation

    It follows from conserving both momentum and kinetic energy. Source: 11 Physics Book FBISE, p. 47.

25. Question 25

    Two bodies of equal mass collide elastically head-on. After the collision they:
    • ABoth stop
    • BStick together
    • CExchange velocities
    • DKeep their velocities
    Show answer and explanation

    Answer: C) Exchange velocities

    If the target was at rest, the first stops and the second moves off with its velocity. Source: 11 Physics Book FBISE, p. 48.

26. Question 26

    A light ball hits a massive body at rest elastically (e.g. a ball thrown at a wall). The light ball:
    • ADoubles its speed
    • BStops completely
    • CMoves on at same speed
    • DRebounds with same speed
    Show answer and explanation

    Answer: D) Rebounds with same speed

    The massive body stays at rest. Source: 11 Physics Book FBISE, p. 48.

27. Question 27

    A massive body hits a light body at rest elastically. The light body moves off with:
    • ATwice the initial velocity
    • BHalf the initial velocity
    • CThe same initial velocity
    • DZero velocity
    Show answer and explanation

    Answer: A) Twice the initial velocity

    The heavy body continues almost unchanged. Source: 11 Physics Book FBISE, p. 48.

28. Question 28

    In an inelastic collision, the kinetic energy lost is changed into:
    • AExtra momentum
    • BHeat, sound and deformation
    • CMass of the bodies
    • DNothing; it is destroyed
    Show answer and explanation

    Answer: B) Heat, sound and deformation

    Momentum is still conserved. Source: 11 Physics Book FBISE, p. 46.

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