Elastic Collision — NEET Physics MCQs with Solutions
Free NEET Physics Elastic Collision MCQs with step-by-step solutions (20 questions). Part of Collision. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Elastic Collision · easy · numerical
A 3 kg ball moving at 8 m/s collides head-on elastically with an identical 3 kg ball at rest. What is the velocity of the second ball after the collision?
A. 8 m/s ✓ Correct
B. 6 m/s
C. 4 m/s
D. 2 m/s
Solution: In an elastic collision between equal masses, velocities are exchanged: the first ball stops and the second moves off at 8 m/s.
Q2 — Elastic Collision · easy · numerical
Two identical 4 kg balls move in the same direction at 10 m/s and 4 m/s. The faster ball catches up and collides head-on elastically with the slower one. What is the velocity of the faster ball just after the collision?
A. 6 m/s
B. 10 m/s
C. 4 m/s ✓ Correct
D. 7 m/s
Solution: Equal masses exchange velocities in an elastic collision, so the ball that was moving at 10 m/s now moves at 4 m/s.
Q3 — Elastic Collision · easy · numerical
A 5 kg block moving at 9 m/s collides head-on elastically with another 5 kg block moving at 3 m/s in the same direction. Find the velocity of the slower block after the collision.
A. 9 m/s ✓ Correct
B. 6 m/s
C. 3 m/s
D. 12 m/s
Solution: Equal masses exchange velocities: the slower block moves off at 9 m/s while the other slows to 3 m/s.
Q4 — Elastic Collision · easy · numerical
A 6 kg ball moving at 8 m/s strikes a 2 kg ball at rest in a head-on elastic collision. What is the velocity of the 2 kg ball after the collision?
A. 4 m/s
B. 12 m/s ✓ Correct
C. 8 m/s
D. 6 m/s
Solution: v₂ = 2m₁u₁/(m₁ + m₂) = (2 × 6 × 8)/8 = 12 m/s, while the 6 kg ball continues at 4 m/s (momentum: 48 = 24 + 24).
Q5 — Elastic Collision · easy · numerical
A 3 kg body moving at 4 m/s makes a head-on elastic collision with a 1 kg body at rest. What is the velocity of the 3 kg body after the collision?
A. 1 m/s
B. 2 m/s ✓ Correct
C. 4 m/s
D. 6 m/s
Solution: v₁ = (m₁ − m₂)u₁/(m₁ + m₂) = (3 − 1)(4)/4 = 2 m/s, while the 1 kg body moves off at 6 m/s.
Q6 — Elastic Collision · easy · numerical
A 1 kg ball moving at 6 m/s hits a stationary 2 kg ball in a head-on elastic collision. Find the velocity of the 2 kg ball after impact.
A. 6 m/s
B. 4 m/s ✓ Correct
C. 2 m/s
D. 3 m/s
Solution: v₂ = 2m₁u₁/(m₁ + m₂) = (2 × 1 × 6)/3 = 4 m/s; the 1 kg ball rebounds at 2 m/s (momentum: 6 = −2 + 8).
Q7 — Elastic Collision · easy · numerical
A 2 kg ball moving at 3 m/s collides head-on elastically with a 4 kg ball at rest. With what speed does the 2 kg ball rebound?
A. 2 m/s
B. 1 m/s ✓ Correct
C. 3 m/s
D. 1.5 m/s
Solution: v₁ = (m₁ − m₂)u₁/(m₁ + m₂) = (2 − 4)(3)/6 = −1 m/s, i.e. it rebounds at 1 m/s while the 4 kg ball moves at 2 m/s.
Q8 — Elastic Collision · easy · numerical
A 1 kg ball moving at 12 m/s collides head-on elastically with a stationary ball that is very much heavier than it. What is the approximate velocity of the 1 kg ball after the collision?
A. ≈ 6 m/s, opposite to its initial direction
B. It comes to rest
C. ≈ 24 m/s, opposite to its initial direction
D. ≈ 12 m/s, opposite to its initial direction ✓ Correct
Solution: When m₂ ≫ m₁, v₁ = (m₁ − m₂)u₁/(m₁ + m₂) ≈ −u₁, so the light ball rebounds with nearly its original speed of 12 m/s.
Q9 — Elastic Collision · easy · numerical
A very heavy body moving at 5 m/s collides head-on elastically with a 2 kg ball at rest. What is the approximate speed of the 2 kg ball after the collision?
A. ≈ 20 m/s
B. ≈ 10 m/s ✓ Correct
C. ≈ 5 m/s
D. ≈ 2.5 m/s
Solution: When m₁ ≫ m₂, v₂ = 2m₁u₁/(m₁ + m₂) ≈ 2u₁ = 2 × 5 = 10 m/s.
Q10 — Elastic Collision · easy · numerical
A 1 kg body moving at 4 m/s makes a head-on elastic collision with a 3 kg body at rest. What fraction of its kinetic energy is transferred to the 3 kg body?
A. 25%
B. 60%
C. 75% ✓ Correct
D. 50%
Solution: Fraction transferred = 4m₁m₂/(m₁ + m₂)² = (4 × 1 × 3)/16 = 3/4 = 75% (the 3 kg body carries 6 J of the initial 8 J).
Q11 — Elastic Collision · easy · numerical
A 2 kg ball moving at 12 m/s strikes a 6 kg ball at rest in a head-on elastic collision. What percentage of its initial kinetic energy does the 2 kg ball retain after the collision?
A. 50%
B. 25% ✓ Correct
C. 75%
D. 33%
Solution: Fraction retained = ((m₁ − m₂)/(m₁ + m₂))² = ((2 − 6)/8)² = 1/4 = 25%; it rebounds at 6 m/s, keeping 36 J of the initial 144 J.
Q12 — Elastic Collision · easy · numerical
Two identical 4 kg balls approach each other with speeds 5 m/s and 3 m/s and collide head-on elastically. What is the velocity of the ball that was moving at 5 m/s after the collision?
A. It comes to rest
B. 3 m/s, along its original direction
C. 5 m/s, opposite to its original direction
D. 3 m/s, opposite to its original direction ✓ Correct
Solution: Equal masses exchange velocities in a head-on elastic collision, so the 5 m/s ball now moves at 3 m/s opposite to its original direction.
Q13 — Elastic Collision · medium · numerical
A 3 kg ball moving at 10 m/s collides head-on elastically with a 6 kg ball moving at 4 m/s in the same direction. What is their speed of separation after the collision?
A. 6 m/s ✓ Correct
B. 12 m/s
C. 14 m/s
D. 3 m/s
Solution: In an elastic collision the relative velocity is reversed: speed of separation = speed of approach = 10 − 4 = 6 m/s.
Q14 — Elastic Collision · medium · numerical
A 3 kg ball moving at 8 m/s makes a head-on elastic collision with a 5 kg ball at rest. Find the velocity of the 5 kg ball after the collision.
A. 4.8 m/s
B. 6 m/s ✓ Correct
C. 3 m/s
D. 8 m/s
Solution: v₂ = 2m₁u₁/(m₁ + m₂) = (2 × 3 × 8)/8 = 6 m/s; the 3 kg ball rebounds at 2 m/s (momentum check: 24 = −6 + 30).
Q15 — Elastic Collision · medium · numerical
A 4 kg body moving at 5 m/s hits a 1 kg body at rest in a head-on elastic collision. What kinetic energy does the 1 kg body carry away?
A. 25 J
B. 18 J
C. 50 J
D. 32 J ✓ Correct
Solution: v₂ = 2m₁u₁/(m₁ + m₂) = (2 × 4 × 5)/5 = 8 m/s, so KE = ½ × 1 × 8² = 32 J of the initial 50 J.
Q16 — Elastic Collision · medium · numerical
A 4 kg ball moving at 8 m/s collides head-on elastically with a 2 kg ball moving at 2 m/s in the same direction. What is the velocity of the 2 kg ball after the collision?
A. 12 m/s
B. 8 m/s
C. 10 m/s ✓ Correct
D. 4 m/s
Solution: v₂ = (2m₁u₁ + (m₂ − m₁)u₂)/(m₁ + m₂) = (64 − 4)/6 = 10 m/s; the 4 kg ball slows to 4 m/s, conserving momentum (36 = 16 + 20).
Q17 — Elastic Collision · medium · numerical
A 2 kg ball moving with speed u makes a head-on elastic collision with a 4 kg ball at rest, after which the 4 kg ball moves at 6 m/s. Find u.
A. 9 m/s ✓ Correct
B. 6 m/s
C. 12 m/s
D. 4.5 m/s
Solution: v₂ = 2m₁u/(m₁ + m₂) gives 6 = 4u/6, so u = 9 m/s; the 2 kg ball rebounds at 3 m/s (momentum: 18 = −6 + 24).
Q18 — Elastic Collision · medium · numerical
A ball moving at 6 m/s approaches a very heavy plate that is moving toward it at 3 m/s. If the collision is elastic, with what speed does the ball move after the collision?
A. 6 m/s
B. 15 m/s
C. 12 m/s ✓ Correct
D. 9 m/s
Solution: The relative speed is reversed: approach speed = 6 + 3 = 9 m/s, so after impact the ball separates from the plate at 9 m/s, i.e. it moves at 9 + 3 = 12 m/s.
Q19 — Elastic Collision · medium · numerical
A 6 kg ball moving at 9 m/s collides head-on elastically with a stationary ball and continues in the same direction at 3 m/s. What is the mass of the other ball?
A. 4 kg
B. 2 kg
C. 6 kg
D. 3 kg ✓ Correct
Solution: v₁ = (m₁ − m₂)u₁/(m₁ + m₂): 3 = 9(6 − m₂)/(6 + m₂) gives m₂ = 3 kg, which moves off at 12 m/s (momentum: 54 = 18 + 36).
Q20 — Elastic Collision · medium · numerical
A 6 kg ball moving at 5 m/s strikes a 4 kg ball at rest in a head-on elastic collision. What impulse does the 4 kg ball receive?
A. 30 N·s
B. 12 N·s
C. 24 N·s ✓ Correct
D. 6 N·s
Solution: v₂ = 2m₁u₁/(m₁ + m₂) = (2 × 6 × 5)/10 = 6 m/s, so impulse = m₂v₂ = 4 × 6 = 24 N·s (the 6 kg ball slows from 5 m/s to 1 m/s).