Question
Two identical pucks collide on an air hockey table. One puck was originally at rest. (a) If the incoming puck has a speed of 6.00 m/s and scatters to an angle of $30.0^\circ$, what is the velocity (magnitude and direction) of the second puck? (You may use the result that $\theta_1 - \theta_2 = 90^\circ$ for elastic collisions of objects that have identical masses.) (b) Confirm that the collision is elastic.

a) $v_1 = 5.20 \textrm{ m/s, } 30^\circ \textrm{ above positive x-axis}$

$v_2 = 3.00 \textrm{ m/s, } 60^\circ \textrm{ below positive x-axis}$

b) Yes, the collision is elastic since the total kinetic energy before the collision is the same as the total kinetic energy after the collision.

Solution Video