Two identical balls moving in opposite directions with speeds 20m/s and 25m/s undergo head on perfectly inelastic collision. The speed of combined mass after collision is 1. 20m/s 2. 22.5m/s 3. 25m/s 4. 2.5m/s

Asked by KRISHPATEL.soc | 22nd Apr, 2022, 04:19: PM

Expert Answer:

Let u1 = 25 m/s and u2 = -20 m/s are velocities of identical balls before collision
 
Total initial momentum before collision  = m u1 + m u2 = ( m × 25 ) - ( m × 20 ) =  5m
 
Collision is perfectly inelastic , i.e. masses are combined together
 
Total  momentum after collision = ( 2m v )
 
where v is final velocity of combined mass
 
By conservation of momentum ( 2 m v ) =  5m   or v = 2.5 m/s

Answered by Thiyagarajan K | 22nd Apr, 2022, 10:48: PM