Answer to Question #49663 in Mechanics | Relativity for Sami

Question

A car of weight 11000N drives up a hill that is 500m high and is 3.75km long at a constant speed of 20ms-1. The friction force acting on the car is 550N


a) Calculate the time for the car to get to the top
b) Calculate the work done in getting to the top of the hill (taking into account friction)
c) Calculate the power developed by the engine in getting to the top of the hill using your answers from a and b
d) From the top of the hill the road goes in a straight line downwards for 6.40km, dropping a total height of 500m. To save fuel the driver switches off the engine and the car free wheels down the hill.
Calculate the speed of the car at the bottom of the hill if the force of friction is 500N
e) Calculate acceleration of the car down the hill