McDowall: In our experiment with the string,
were you pushing or pulling on the object
to make the object travel in a circular path?
Noah: I was pulling on the string.
McDowall: What path will the object take if
the string breaks?
Noah: If the string breaks, the object will
travel in a straight line.
McDowall: If a centrifugal or outward force
existed what direction would you expect the
object to take if the string breaks?
Noah: Well, if centrifugal force existed,
I believe the object will travel in an outwards
motion.
McDowall: Let’s watch and see what happens
if the student releases the string.
Here we have superimposed the path of the
object up to and after the time that the string
is released.
As soon as you stop pulling on the string
(applying an inward, not an outward force)
the object will travel in a straight line.
With no inward force, the object no longer
travels on a circular path.
Any object changing direction experiences
a force.
If the object is to travel in a circular path,
it must experience a center seeking force.
This is called the centripetal force.
