Question

a car is traveling at 20m/s along a road. a child runs out into the road 50 m ahead and the car driver steps on the break. what must the car's decelaration be if the car is to stop just before it reaches the child.

Answer 1

Answer:

4 m/s²

Explanation:

$v {}^{2} = {u}^{2} + 2as \\ 0 {}^{2} = {20}^{2} + 2a(50) \\ a = - 4ms {}^{ - 2}$

Therefore, deceleration = 4 m/s²