Q.

A stationary particle breaks into two parts of masses mA and mB, which move with velocities vA and vB respectively. The ratio of their kinetic energies (KB:KA) is             [2024]

1 mB:mA  
2 1:1  
3 mBvB:mAvA  
4 vB:vA  

Ans.

(4)

By conservation of linear momentum

0=mAVA+mBVB

mAVA=-mBVB

mAVA=mBVB

K=P22mK1m

KBKA=mAmBKBKA=vBvA