A hockey puck slides into a brick

A hockey puck of mass m₁ = 2 kg slides at v_i = 15 m/s due East. It bumps into a stationary brick of mass m₂ = 5 kg. Afterwards, the puck slides away to the northeast with velocity v_1f = 8 m/s at θ₁ = 10 degrees, and the brick slides to the southeast at v_2f at θ₂ = 11 degrees,

Which of the following is the final speed of the brick?

1. 1.55 m/s
2. 2.16 m/s
3. 2.90 m/s

Is this an elastic collision? That is, does it conserve kinetic energy?

1. yes
2. no

Copyright © Michael Richmond. This work is licensed under a Creative Commons License.