Question

Two equal masses $m_{1}$ and $m_{2}$ moving along the same straight line with velocities + 3 m/s and – 5 m/s respectively collide elastically. Their velocities after the collision will be respectively

• A.
  • 4 m/s for both
• B. – 3 m/s and +5 m/s
• C. – 4 m/s and + 4 m/s
• D. – 5 m/s and + 3 m/s

Answer 1

Answer: (D)

– 5 m/s and + 3 m/s

Answer 2

As $m _ { 1 } = m _ { 2 }$ therefore after elastic collision velocities of masses get interchanged

i.e. velocity of mass $m _ { 1 } = - 5 \mathrm {~m} / \mathrm { s }$

and velocity of mass $m _ { 2 } = + 3 \mathrm {~m} / \mathrm { s }$