Problem 41.

A motor scooter travels east at a speed of 13 m/s. The driver then reverses direction and heads west at 17 m/s.  What was the change in velocity of the scooter?

Solution:

By definition the change in the velocity is equal to final velocity minus initial velocity.

The final velocity is 17 m/s pointing west. The initial velocity is 13 m/s pointing east. Since the velocity is a vector we need to describe the change of the velocity in terms of the components.

We choose the coordinate axis pointing to the west. Then the component of the final velocity is +17 m/s, and the component of the initial velocity is -13 m/s. Then the change in the velocity is

17 – (-13) = 30 m/s