Question

When the driver presses the brake pedal, his car stops with an acceleration of - 8.7 m/s. How far will the car travel while coming to a complete stop if its initial speed is 10 m/s? A. 10.2 m B. 13.1 m C. 9.5 m D. 5.7m

Answer 1

Answer:

D. 5.7 m

Explanation:

The acceleration of the car is -8.7 m/s² and the car has an initial speed (u) of 10 m/s. The car said to come to rest, that means that the final velocity (v) of the car is 0 m/s.

To find the distance traveled by the car (s) before complete stop, this equation is being used:

v² = u² + 2as

$2as=v^2-u^2\\s=\frac{v^2-u^2}{2a}\\ Substituting:\\s=\frac{0-10^2}{2*-8.7}\\ s=\frac{-100}{17.4}\\ s=5.7\ m$

The car traveled 5.7 m before coming to a complete stop