Chronology | Current Month | Current Thread | Current Date |
[Year List] [Month List (current year)] | [Date Index] [Thread Index] | [Thread Prev] [Thread Next] | [Date Prev] [Date Next] |
One of the first things I show students when we get to circular
motion is an Interactive Physics simulation of a racecar going around
a track. I just use it to show the direction of the velocity and
acceleration vectors. The car is held to the circular path by a rope
and after a couple of laps, I have the rope break. It was my
intention to show that without the centripetal force, the car goes in
a straight line. But the first time I ran it, I admit that I was
surprised to see the car move off in a straight line, but also rotate
-- it was actually a very realistic view of a car "spining out". But
I wasn't expecting it and I thought "What makes the car start to
rotate?". Then I realized that the car didn't START to rotate -- it
was already "rotating" as it circled the track, just like the moon.
In fact, observers in the center of the track would never see the
dark side of the car. You can even time the rotations after the rope
breaks and see that the period matches the period of the circular
motion.