Problem 10.

A car is initially traveling due north at 23 m/s.
(a) Find the velocity of the car after 4 s if its acceleration is due north.
(b) Find the velocity of the car after 4 s if its acceleration is instead due south.

Solution:

This is the motion with constant acceleration. The dependence of velocity on time is given by the equation:

Where .

(a) In this case the direction of acceleration is the same as the direction of initial velocity. Then and we have

(b) In this case the direction of acceleration is opposite to the direction of initial velocity. Then and we have