Question

A polar bear starts at the North Pole. It travels 1.0 km south, then 1.0 km east, then 1.0 km north, then 1.0 km west to return to its starting point. This trip takes 45 min.
What was the bear's average speed?

Answer 1

Answer:

The average speed of the bear is 5.3 km/h.

Explanation:

Hi there!

The average speed is calculated as the distance traveled divided by the time in which that distance was covered. The bear traveled 4 km (1 km south, 1 km east, 1 km north and 1 km west) in 45 min. It does not matter the direction at which the bear traveled, only how much distance the bear moved. So the average speed (a.s) will be:

a.s = d/t

Where:

d = traveled distance.

t = time in which that distance was covered.

$a.s = \frac{4 km}{45 min(\frac{1 h}{60 min}) } = 5.3\frac{km}{h}$

The average speed of the bear is 5.3 km/h.

Notice that if the question would have asked to find the average velocity, the answer would have been zero because the total displacement of the bear was zero (it returned to the initial point). The average velocity is calculated as the displacement over time.