# Kinetic Energy

1. Oct 20, 2007

### pinkyjoshi65

why it is necessary to reduce speed in towns or areas with pedestrians compared to a fast highway.

We have to use concepts of Kinetic energy, frictional force and work to figure out the answer..

So..if a person is travelling at a high speed (hence the Kinetic energy is high) in a town, then he will have to do more work to stop the car suddenly. Anyone willing to add in..?

2. Oct 20, 2007

### pinkyjoshi65

Frition is the force opposing the motion of the car. So when the car is brought to a stop, only friction acts on all the tires, since the foot frm the accelerator is removed. This should be done properly since for a given speed of the car, the wheels need to rotate at a particular rate if the car is not to skid.In other words, if a driver jams on his brakes so that the wheels stop turning too quickly then the car will not come to a halt at the instant that the wheels stop but the car will slide across the surface of the road for a while. Hence it is best that the car is moving at a slow speed. This is what i could get out of this..