A ball of mass 0.5kg moving with a velocity of 10ms-1 makes a head on collision with a ball B of mass 2kg moving with a velocity of 9ms-1 in the opposite direction . If A and B stick together after collision , calculate the common velocity in the direction of A .

Answer 1

By conservation of momentum:

m1v1 + m2v2 = (m1 + m2)vf

where m1 and v1 are the mass and velocity of ball A before the collision, m2 and v2 are the mass and velocity of ball B before the collision, and vf is the common velocity of the two balls after the collision.

Plugging in the given values:

(0.5 kg)(10 m/s) + (2 kg)(-9 m/s) = (0.5 kg + 2 kg)vf

5 kg m/s - 18 kg m/s = 2.5 kg vf

-13 kg m/s = 2.5 kg vf

vf = -5.2 m/s

Since the question asks for the common velocity in the direction of A, we take the magnitude of vf (5.2 m/s) but add a positive sign:

Common velocity in direction of A = 5.2 m/s