A scooterist moving with a speed of
36 km h-1 sees a child standing in the
middle of the road. He applies the brakes
and brings the scooter to rest in 5 s just in
time to save child. If mass of the scooter
and driver is 300 kg, the average retarding
force on the scooter is
A 6 × 107 g cm s-2
B 6 × 104 g m s-2
C 6 × 105 kg cm s-2
D 6 × 103 kg m s-2