Question

The driver in a car of total mass 800kg and which is travelling at 20m / s suddenly observes a stationary dog in his path 50m ahead . if the car brakes can exert a force of 2000N, what will likely happen

Answer 1

f = m a ... 2000 = 800 * a ... a = 2.5 m/s^2

it takes 8 s to stop ... 20 m/s / 2.5 m/s^2

average velocity during stop
... (20 + 0) / 2 = 10 m/s

... sorry, pooch ...