Question

A car is travelling 20m/s along a road . A child run out on the road 50 m ahead and the car driver applied the break. What must be retardation of car if car is to stop just near the child.​

Answer 1

Answer:

Initial velocity, u=20m/s

Final velocity, v=0m/s

Distance, s=50m

Using relation, v^2=u^2+2as

0^2 =(20)^2+2×a×50

0^2=400+100a

−400=100a

a= 100/−400

=−4m/s^2

The car's deceleration must be 4m/s^2