Question

A car moves in a straight line at 24.0 m/s for 10.0 miles, then at 30.0 m/s for another 10.0 miles.

(a) Is the car's average speed less than, greater than, or equal to 27.0 m/s?
less than 27.0 m/s
equal to 27.0 m/s
greater than 27.0 m/s

(b) Calculate the car's average speed. (Enter your answer to three significant figures.)

Answer 1

1 mile = 1609 meters
10 miles = 16090 meters

16090m/(24.0m/s) = 670s
16090m/(30.0m/s) = 536s

Average Speed = Total distance/Elapsed time
Average Speed = [16090m(2)]/(670s+536s) = 32080m/1206s = 26.7m/s

(a) The car's average speed is less than 27.0m/s
(b) The car's average speed is 26.7m/s

Answer 2

One typo: In the average speed calculation, 16090m(2) = 32180m, 32080m. The final answer is still correct.