Turning a Car
Turning a car, or driving a car around a curve, is a very common
experience for many people. What is the physics of this event?
First, A Little Review:
Acceleration is a
vector quantity. So, we know that no matter what else might be going
on, a turning car is accelerating - even if its speed is
constant - since it is changing direction. This is a centripetal
(center-pointing) acceleration. Newton's
Second Law says that accelerations are caused by forces,
so there must be a force on the car while it is turning. This force
is the inward-pointing centripetal force, as shown in the diagram at
right. This centripetal force is the net
force on the car.
The diagram above shows a car (blue rectangle) going
around a turn (top view). There must be a centripetal
(center-pointing) force on the car.
We also know that forces are interactions between objects.
Something must be exerting the centripetal force - it doesn't "just
happen." What is exerting the centripetal force on the car? Well, it
depends on the situation...
last update January 11, 2008 by JL