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

4 m/s²

Step-by-step explanation:

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

Therefore, deceleration = 4 m/s²