Question

A 0.384 kg puck, initially at rest on a horizon-
tal, frictionless surface, is struck by a 0.189 kg
puck moving initially along the x axis with
a speed of 2.7 m/s. After the collision, the
0.189 kg puck has a speed of 1.7 m/s at an
angle of 28 to the positive x axis.
Determine the velocity of the 0.384kg puck
after the collision.
Answer in units of m/s

Answer 1

Linear momentum must be preserved. You do not have to assunme an elastic collision. Total momentum remains zero along the y direction. That will tell you the y momentum and velocity component of the 0.384 kg puck.

0.189*1.7 sin 28 = -0.384 Vy
Solve for Vy.

For the x component, Vx, require total momentum conservation in the x direction

0.189*2.7 = 0.189*1.7*cos28 + 0.384*Vx