A 1500 kg car travels along the road at 25 m/s when the driver sees the light turn red and applies the brakes. What average force is needed to stop the car in a) 5 seconds and b) .2 seconds?

Question

A 1500 kg car travels along the road at 25 m/s when the driver sees the light turn red and applies the brakes. What average force is needed to stop the car in a) 5 seconds and b) .2 seconds?
What formula should be used?

drwls · Answer

Force*Time = Initial momentum = 1500*25 kg m/s Divide 3.75*10^4 by the time interval to get the force, which will be in Newtons.

camille · Answer

1500*25=60^2=120