# Grantham PHY220 Week 1 Assignment Problem 5

### A car travels 120 meters in one direction in 20 seconds. Then the car returns ¾ of the way back in 10 seconds. Calculate the average speed of the car for the first part of the trip. Find the average velocity of the car.

Solution:

The average speed of the car for the first part of the trip is

$average\:speed=\frac{x}{t}=\frac{120\:m}{20\:s}=6\:m/s\:$

The average velocity of the car is

$\overline{v}=\frac{\Delta x}{\Delta t}=\frac{120-\frac{3}{4}\left(120\right)\:m}{20+10\:s}=\frac{30\:m}{30\:s}=1\:m/s$