Question

An 1100-kg car traveling at 27.0 m/s starts to slow down and comes to a complete stop in 578 m. What is the magnitude of the average braking force acting on the car?

Answer 1

$<F>=\frac As=\frac{mv^2}{2s},$

$<F>=\frac{1100\cdot 27^2}{2\cdot 578}=694~N.$