posted by Mara .
A(n) 840-kg dragster accelerates on a race track from rest to 85 km/h in 0.90 seconds.
(a) What is the change in momentum of the dragster?
(b) What is the average force exerted on the dragster?
(c) What exerts that force?
(a) Multiply m by the change in V. Convert the final speed to m/s first.
(b) Average force = (momentum change)/time
(c) The track exerts the force against the tires.
a) If you did not know before, momentum is equal to mass times velocity, p=mv.
The others, "drwls", has explained it well enough for you.