A 20 kg ball moving with a velocity collides with a 30 kg ball initially at rest .if both of them coalesce ,then final velocity of the combined mass is 

a) 
b) 
c) 
d) 
A 20 kg ball moving with a velocity collides with a 30 kg ball initially at rest .if both of them coalesce ,then final velocity of the combined mass is 

a) 
b) 
c) 
d) 
(d) From conservation of momentum. Momentum before collision =Momentum after collision 20 Or
