00:01
For this problem on the topic of momentum and collisions, we are told that a racquet ball, which has a mass of 41 .97 grams and a speed of 15 .69 meters per second, collides with a wall of a quart at an angle of 48 .67 degrees relative to the normal.
00:17
The racket ball then leaves the wall at an angle of 55 .75 degrees relative to the normal, and we want to know the coefficient of restitution of the ball.
00:27
Now, using our diagram before and after the collision, we can see that after the collision, the angle at which the racquet ball leaves the wall, the tann of that angle, rather, tan theta f, is equal to the component of the ball's final momentum that is parallel to the wall divided by the component of the ball's final momentum that is perpendicular to the wall.
00:55
And so this angle theta f is equal to the arc tan, of the parallel component of the final momentum over the perpendicular component of the final momentum.
01:13
Now we know from the conservation of momentum that the parallel component of the final momentum must equal the parallel component of the initial momentum which is from the diagram pi sine theta i...