On an ice skating rink, a girl of mass 50 kg stands stationary, face to face with a boy of mass 80 kg. the children push off of one another, and the boy moves away with a velocity of +3 m/s. what is the final velocity of the girl? –1.9 m/s +1.9 m/s –4.8 m/s +4.8 m/s

- 4.8 m/s option (c)

Explanation:

Let the girl moves with velocity u.

mass of girl, m = 50 kg, u = ?

mass of boy, M = 80 kg, U = + 3 m/s

Use the conservation of momentum

momentum before pushing = momentum after pushing

0 = m x u + M x U

0 = 50 x u + 80 x 3

- 240 / 50 = u

u = - 4.8 m/s

answer: good job it's all correct !

explanation:

be subject to a force andchange its motion