Answer to Question #176565 in Physics for kate

Question

A net force of –8750N is used to stop of 1250.kg car travelling 25m/s. What braking distance is needed to bring the car to a halt?

Answer 1

Let's first find the deceleration of the car:

$$a=\dfrac{F}{m}=\dfrac{–8750\ N}{1250\ kg}=-7\ \dfrac{m}{s^2}.$$

Finally, we can find the braking distance needed to bring the car to a halt:

$$v^2=v_0^2+2as,$$ $$0=v_0^2+2as,$$ $$s=\dfrac{-v_0^2}{2a}=\dfrac{-(25\ \dfrac{m}{s})^2}{2\cdot(-7\ \dfrac{m}{s^2})}=44.64\ m.$$