Question

You travel 20.0 mph for 0.500 hour, 40.0 mph for 1.00 hour, 30.0 mph for 0.500 hour, and 50.0 mph for 2.00 hours. What is the average speed?

165mph
65mph
23.5mph
41.3mph

Answer 1

The average speed is 41.3 mph.

Step-by-step explanation:

I complete the travel in 4 sections.

In the first section I travelled: 20 m/h . 0.5 h = 10 m

In the second section I travelled: 40 m/h . 1 h = 40 m

In the third section I travelled: 30 m/h . 0.5 h = 15 m

In the fourth section I travelled: 50 m/h . 0.5 h = 100 m

In total I travelled 165 meters.

d = 10 m + 40 m + 15 m + 100 m = 165 m

The time used to do this travel was 4 hours.

t = 0.5 h + 1 h +0.5 h + 2 h = 4 h

The average speed is s = d / t = 165 m / 4 h = 41.25 m/ h ≅ 41.3 mph