Question

Ball a of mass 5.0 kilograms moving at 20 meters per second collides with ball b of unknown mass moving at 10 meters per second in the same direction. after the collision, ball a moves at 10 meters per second and ball b at 15 meters per second, both still in the same direction. what is the mass of ball b? * 1 point your answer

Answer 1

M = mass of the ball A = 5.0 kg

m = mass of the ball B = ?

V = initial velocity of the ball A before collision = 20 m/s

v = initial velocity of the ball B  before collision = 10 m/s

V' = final velocity of the ball A after collision = 10 m/s

v' = final velocity of the ball B after collision = 15 m/s

using conservation of momentum

M V + m v = M V' + m v'

(5.0) (20) + m (10) = (5.0) (10) + m (15)

100 + 10 m= 50 + 15 m

5 m = 50

m= 10 m/s