Question

A person walks first at a constant speed of 5.40 m/s along a straight line from point to point and then back along the line from to at a constant speed of 3.10 m/s. (a) What is her average speed over the entire trip

Answer 1

Answer: The average speed over the entire trip is 3.94 m/s

Explanation:

As we know : $speed=\frac{distance}{time}$

Let the distance of straight line from point to point be = d

Total distance covered = 2d

Time taken to cover the forward journey = $\frac{d}{5.40}$

Time taken to cover the backward journey = $\frac{d}{3.10}$

Total time for the journey = Time taken to cover the forward journey  + Time taken to cover the backward journey  = $\frac{d}{5.40}+\frac{d}{3.10}$

Average speed = $\frac{\text {total distance}}{\text {total time}}=\frac{2d}{\frac{d}{5.40}+\frac{d}{3.10}}=3.94m/s$

Thus  average speed over the entire trip is 3.94 m/s