Q. 48

Expert-verified
Found in: Page 289

### Physics for Scientists and Engineers: A Strategic Approach with Modern Physics

Book edition 4th
Author(s) Randall D. Knight
Pages 1240 pages
ISBN 9780133942651

# One billiard ball is shot east at m/s. A second, identical billiard ball is shot west at m/s. The balls have a glancing collision, not a head-on collision, deflecting the second ball by 90° and sending it north at m/s. What are the speed and direction of the first ball after the collision? Give the direction as an angle south of east.

The speed and direction of the first ball after the collision is

See the step by step solution

## Step 1. Given information

At a speed of m/s, one billiard ball is fired east. At m/s, a second identical billiard ball is fired west. The balls collide glancingly rather than head-on, diverting the second ball 90 degrees and propelling it north at 1.41 m/s.

## Step 2. Analyze and apply

Ball 1 represents a ball moving east (positive x-axis direction) while ball 2 represents a ball moving west (negative x-axis direction). Then there's the fact that the north is up, or that the y axis is moving in the right direction. We know that momentum can only be conserved if all of its components are conserved. As a result, for the x component, we have:

## Step 3. Evaluate in another direction

For y-axis:

The final speed,

The direction of the first ball,