Inertia and the Right
Hand Turn
A GIF Animation
Many students of physics do not believe in centripetal
("inwards") forces. Even after completion of a thorough physics
course, such students will still incorrectly believe that an object
moving in a circle experiences an outward force. Perhaps the reason
for adhering to this misconception stems from their experiences with
riding as a passenger in automobiles and amusement park rides.
Imagine that you are a passenger in a car which is making a
right-hand turn. As the car begins to take the turn to the right, you
often feel as though you are sliding to the left. The car is
turning to the right due to the inward force, yet you
feel as though you are being forced leftward or outward. In
actuality, the car is beginning its turning motion (to the right)
while you continue in a straight line path. This motion can be better
understood by examining the animation below.
Observe in the animation that the passenger (in blue) continues
in a straight-line motion for a short period of time after the car
begins to make its turn. In fact, the passenger follows a
straight-line path until striking the shoulder of the driver (in
red). Once striking the driver, a force is applied to the passenger
to force the passenger to the right and thus complete the turn.
An inward net force is required to make a turn in a circle. This
inward net force requirement is known as a centripetal force
requirement. In the absence of any net force, an object in motion
(such as the passenger) continues in motion in a straight line at
constant speed. This is Newton's first law of motion. While the car
begins to make the turn, the passenger and the seat begin to edge
rightward. As such, the car is beginning to slid out from under
the passenger. Once striking the driver, the passenger can now turn
with the car and experience some circle-like motion.
For more information on physical descriptions of motion,
visit
The
Physics Classroom. Specific information on circular motion will
be available soon at The Physics Classroom.
This page was created by
Tom
Henderson of
Glenbrook South
High School.
Comments and suggestions can be sent by e-mail to
Tom
Henderson.
This page last updated on 6/5/97.