Question

Two hockey players are traveling at velocities of v1 = 10 m/s and v2 = -22 m/s when they undergo a head-on collision. after the collision, they grab each other and slide away together with a velocity of -3.6 m/s. hockey player 1 has a mass of 123 kg. what is the mass of the other player?

Answer 1

The negative sign in the velocity simply indicate direction, nothing else. From the conservation of momentum, we have the equation:

m1 v1 + m2 v2 = (m1 + m2) v’

 

123 kg (10 m/s) + m2 (-22 m/s) = (123 kg + m2) (-3.6 m/s)

1230 – 22 m2 = -442.8 – 3.6 m2

18.4 m2 = 1672.8

m2 = 90.91 kg