gcsescience.com                                               31                                            gcsescience.com

Forces and Motion

Braking Distance of a Car - Conditions.

The braking force which brings a car to a stop depends on friction.

The most important friction occurs between the tyres and the road surface.
If the road is wet or icy,
then friction is reduced and the car will take longer to stop
or the tyres will slip (skid).
The tread on the tyre makes water on the surface of the road
go up into the grooves and then throws the water out sideways
to get it out from under the tyre.
If the tread is not deep enough,
the tyre can not remove surface water quickly
and the tyre will ride up on top of the water
and loose contact with the road (called aquaplaning).

After the road surface and tyre condition,
the next most important friction occurs between the brakes and the wheels.
If the brakes are not seriously worn or malfunctioning,
then friction here is usually very good
because of modern brake design and materials.

back        Headings        Forces and Motion        Search        Questions        next

gcsescience.com            Contents           Index            Quizzes           gcsescience.com

Copyright © 2008 Dr. Colin France. All Rights Reserved.