Below is a well-structured, NCERT-aligned set of 50 MCQs on Laws of Motion, written in a clean, Classic Editor–friendly format (no special blocks, no scripts).
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The questions are section-wise, concept-clearing, and strictly suitable for CBSE Class 11 board-exam standard.
MCQs on Laws of Motion
CBSE Class 11 Physics – MCQs with Answers and Explanations
Course: CBSE Class 11 Physics
Section: Laws of Motion
Topic: MCQs on Laws of Motion
Board: CBSE Board Examinations (NCERT Syllabus Based)
Section A: Newton’s First Law & Inertia (Q1–Q10)
Q1. Newton’s First Law of Motion is also known as:
A) Law of force
B) Law of acceleration
C) Law of inertia
D) Law of momentum
Answer: C
Explanation: The first law describes the tendency of a body to resist any change in its state of rest or uniform motion, which is called inertia.
Q2. Inertia of a body depends upon its:
A) Shape
B) Volume
C) Mass
D) Velocity
Answer: C
Explanation: Greater the mass of a body, greater is its inertia. Mass is the quantitative measure of inertia.
Q3. A person sitting in a moving bus falls forward when the bus suddenly stops due to:
A) Inertia of rest
B) Inertia of motion
C) Force of friction
D) Action–reaction
Answer: B
Explanation: The upper part of the body continues moving due to inertia of motion when the bus stops suddenly.
Q4. When a carpet is beaten with a stick, dust comes out because of:
A) Gravity
B) Friction
C) Inertia of rest
D) Inertia of motion
Answer: C
Explanation: Dust particles tend to remain at rest while the carpet moves, causing separation.
Q5. Which of the following is an example of inertia of rest?
A) A moving fan continues to rotate after switch off
B) A person falls backward when a bus starts
C) A stone thrown upward falls down
D) A rolling ball slows down
Answer: B
Explanation: The person tends to remain at rest while the bus starts moving.
Q6. If no external force acts on a body, it will:
A) Always remain at rest
B) Always move with acceleration
C) Move with constant velocity
D) Come to rest
Answer: C
Explanation: According to Newton’s First Law, the velocity remains constant in absence of net external force.
Q7. Inertia is the property of a body by virtue of which it:
A) Moves faster
B) Changes direction
C) Resists change in motion
D) Produces force
Answer: C
Explanation: Inertia opposes any change in the state of motion or rest.
Q8. Which has greater inertia?
A) A bicycle
B) A car
C) A truck
D) A motorcycle
Answer: C
Explanation: Greater mass means greater inertia; a truck has the largest mass.
Q9. The tendency of a body to remain in uniform circular motion is due to:
A) Force
B) Acceleration
C) Inertia
D) Momentum
Answer: C
Explanation: Inertia resists change in direction as well as speed.
Q10. Inertia of motion is directly proportional to:
A) Speed
B) Shape
C) Mass
D) Area
Answer: C
Explanation: Mass is the measure of inertia, independent of speed or shape.
Section B: Newton’s Second Law, Force & Momentum (Q11–Q25)
Q11. Newton’s Second Law relates force with:
A) Velocity
B) Momentum
C) Displacement
D) Energy
Answer: B
Explanation: The law states that force is proportional to the rate of change of momentum.
Q12. The SI unit of force is:
A) Dyne
B) Joule
C) Newton
D) Watt
Answer: C
Explanation: One newton is the force required to produce an acceleration of 1 m/s² in a mass of 1 kg.
Q13. Momentum of a body is given by:
A) mv²
B) ma
C) mv
D) m/v
Answer: C
Explanation: Momentum is the product of mass and velocity.
Q14. A force of 10 N acts on a mass of 2 kg. The acceleration produced is:
A) 2 m/s²
B) 5 m/s²
C) 10 m/s²
D) 20 m/s²
Answer: B
Explanation: Using F = ma, acceleration = 10/2 = 5 m/s².
Q15. Which of the following is a vector quantity?
A) Speed
B) Mass
C) Momentum
D) Time
Answer: C
Explanation: Momentum has both magnitude and direction.
Q16. The rate of change of momentum is equal to:
A) Energy
B) Force
C) Velocity
D) Power
Answer: B
Explanation: This is the mathematical statement of Newton’s Second Law.
Q17. If net force acting on a body is zero, its momentum will:
A) Increase
B) Decrease
C) Remain constant
D) Become zero
Answer: C
Explanation: Zero net force implies no change in momentum.
Q18. Impulse is equal to:
A) Force × Distance
B) Force × Time
C) Momentum × Velocity
D) Energy × Time
Answer: B
Explanation: Impulse is the product of force and the time for which it acts.
Q19. SI unit of impulse is:
A) N
B) kg
C) Ns
D) J
Answer: C
Explanation: Impulse has units of newton-second.
Q20. A heavy truck requires a longer distance to stop than a car moving with same speed because:
A) Truck has greater friction
B) Truck has more momentum
C) Truck has more acceleration
D) Truck has less inertia
Answer: B
Explanation: Greater mass means greater momentum, requiring more force or time to stop.
Q21. If mass is doubled and force remains same, acceleration becomes:
A) Double
B) Half
C) Four times
D) Zero
Answer: B
Explanation: From a = F/m, doubling mass halves acceleration.
Q22. Seat belts in cars reduce injuries by:
A) Increasing force
B) Decreasing time
C) Increasing stopping time
D) Increasing momentum
Answer: C
Explanation: Increased stopping time reduces force for the same change in momentum.
Q23. A constant force produces motion with:
A) Constant velocity
B) Increasing velocity
C) Zero acceleration
D) Decreasing acceleration
Answer: B
Explanation: A constant force produces constant acceleration.
Q24. The unit of momentum is equivalent to:
A) kg·m/s
B) N/m
C) J/s
D) kg·m²/s²
Answer: A
Explanation: Momentum = mass × velocity.
Q25. Greater the change in momentum in a given time, greater is the:
A) Velocity
B) Energy
C) Force
D) Displacement
Answer: C
Explanation: Force is proportional to rate of change of momentum.
Section C: Newton’s Third Law & Conservation of Momentum (Q26–Q35)
Q26. Newton’s Third Law states that action and reaction forces are:
A) Equal and same direction
B) Unequal and opposite
C) Equal and opposite
D) Acting on same body
Answer: C
Explanation: Forces occur in equal magnitude and opposite direction pairs.
Q27. Action and reaction forces act on:
A) Same body
B) Different bodies
C) Same point
D) Same direction
Answer: B
Explanation: They act on two different interacting bodies.
Q28. Recoil of a gun is due to:
A) Newton’s First Law
B) Newton’s Second Law
C) Newton’s Third Law
D) Gravitation
Answer: C
Explanation: When bullet moves forward, gun moves backward due to action–reaction.
Q29. Conservation of momentum is valid when:
A) External force is present
B) Internal force is zero
C) No external force acts
D) Mass is constant
Answer: C
Explanation: Momentum is conserved in absence of external forces.
Q30. Rocket propulsion works on the principle of:
A) Conservation of energy
B) Conservation of momentum
C) Conservation of mass
D) Inertia
Answer: B
Explanation: Momentum of exhaust gases balances rocket momentum.
Q31. When a person jumps from a boat, the boat moves backward due to:
A) Inertia
B) Friction
C) Conservation of momentum
D) Gravity
Answer: C
Q32. Which law explains walking?
A) First law
B) Second law
C) Third law
D) Law of gravitation
Answer: C
Explanation: Foot pushes ground backward, ground pushes foot forward.
Q33. Action and reaction never cancel each other because:
A) They act on different bodies
B) They are unequal
C) They act at different times
D) They are not forces
Answer: A
Q34. Momentum of a system remains constant if:
A) Net force ≠ 0
B) Only internal forces act
C) Acceleration is present
D) Velocity is zero
Answer: B
Q35. In a collision, momentum is conserved because:
A) Energy is conserved
B) No friction acts
C) External force is zero
D) Bodies are elastic
Answer: C
Section D: Friction & Applications of Laws of Motion (Q36–Q50)
Q36. Friction always acts in a direction:
A) Along motion
B) Opposite to relative motion
C) Vertical
D) Downward
Answer: B
Q37. Which friction is maximum?
A) Rolling friction
B) Sliding friction
C) Static friction
D) Zero friction
Answer: C
Q38. Rolling friction is less than sliding friction because:
A) Area of contact is less
B) Speed is less
C) Force is more
D) Mass is less
Answer: A
Q39. Friction produces:
A) Light only
B) Heat only
C) Sound only
D) Heat and sound
Answer: D
Q40. Lubricants reduce friction by:
A) Increasing roughness
B) Decreasing area
C) Forming a thin layer
D) Increasing pressure
Answer: C
Q41. Walking is possible due to:
A) Sliding friction
B) Static friction
C) Rolling friction
D) No friction
Answer: B
Q42. Brakes in vehicles work on the principle of:
A) Inertia
B) Acceleration
C) Friction
D) Momentum only
Answer: C
Q43. Ice reduces friction because it forms a:
A) Rough layer
B) Sticky layer
C) Water film
D) Dry surface
Answer: C
Q44. If friction were absent, walking would be:
A) Easy
B) Faster
C) Impossible
D) Unchanged
Answer: C
Q45. Friction is useful because it:
A) Always wastes energy
B) Prevents motion
C) Enables movement
D) Destroys energy
Answer: C
Q46. Friction depends on:
A) Area only
B) Nature of surfaces
C) Volume
D) Colour
Answer: B
Q47. Limiting friction is proportional to:
A) Mass
B) Normal reaction
C) Velocity
D) Area
Answer: B
Q48. Tyres have grooves to:
A) Increase speed
B) Reduce weight
C) Increase friction
D) Reduce area
Answer: C
Q49. Which force opposes relative motion at contact?
A) Magnetic
B) Gravitational
C) Frictional
D) Nuclear
Answer: C
Q50. Laws of motion are applicable in:
A) Only rest state
B) Only motion
C) Both rest and motion
D) Only circular motion
Answer: C