question_answer

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 [CBSE PMT 1994, 98; AIIMS 2000]

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

Correct Answer: D

Solution :

As \[{{m}_{1}}={{m}_{2}}\] therefore after elastic collision velocities of masses get interchanged i.e. velocity of mass \[{{m}_{1}}=-5\ m/s\] and velocity of mass \[{{m}_{2}}=+3\ m/s\]