Question

A car is moving at 20 m / s before it applies the brakes for 4 s. It slows at a constant rate to 10 m / s. Five seconds after this, the brakes are applied again and stop the car in 5 seconds. The car slows at a constant rate during this period of time as well. What is the total distance the car travels from the moment the brakes were first applied to the moment it stops?
a) 50 b)25 c)110 d)135

Answer 1

use the average speed on an interval, multiplied by the time of the interval

add the three intervals

Answer 2

if you graph it, velocity vs time, the distance traveled at any time is the area under the graph at that time.