Question

A ball rolled 20.0 m [E] in 7.0 s, hit an obstacle, and rolled straight back. After thecollision, the ball rolled 15.0 m [W] in 7.0 s.What was the average speed of the ball?

Answer 1

ANSWER

2.5 m/s

EXPLANATION

The average speed of an object is,

$\bar{v}=\frac{\Delta x}{\Delta t}$

Where Δx is the total distance traveled and Δt is the total time taken.

In this case, we know that the ball traveled 20 m in the east direction for 7 seconds and then traveled back 15 m in the west direction in the same time. So, the average speed of the ball is,

$\bar{v}=\frac{20m+15m}{7s+7s}=\frac{35m}{14s}=2.5m/s$

Hence, the average speed of the ball is 2.5 m/s.