A ball of mass 100g travelling with a velocity of100m/s collides with another ball of mass 400g moving at 50m/s in the same direction . If the stick together after the impact, calculate their common velocity

The common velocity of the two balls after the impact is 75 m/s. This can be calculated using the equation of conservation of momentum:

m1*v1 + m2*v2 = (m1 + m2)*v

where m1 and m2 are the masses of the two balls, v1 and v2 are their respective velocities, and v is the common velocity after the impact.

Plugging in the given values, we get:

(100g * 100m/s) + (400g * 50m/s) = (500g * v)

Solving for v, we get:

v = 75 m/s