A car is travelling at 20m/s along a road. a child runs out into road 50m ahead and car driver steps on break paddle. what must car retardation rate be if the car is to stop just before it reaches the child?????

Answer 1

V^2 = Vo^2 + 2a*d
a = (V^2-Vo^2)/2d
a = (0-20^2)/100 = -4 m/s^2.