Centripetal Acceleration

Most recent answer: 12/27/2007

Q:
Reference to your reply regarding the ARIFICIAL GRAVITY you wrote that in a spinning wheel one will feel a force to the outer edge!! I did learn that, that is the way the astronauts have arificial Gravity.
During my study about ciccular motion of a body I learned that the object revolving in circle should have an acceleration towards the CENTER [due to centripital force ]
but not in OUTWARD direction. So it should be attracted towards the CENTER. Please reply. Thanks
- Masood Ansari (age 14)
Kuwait
A:
You’re right that to stay in circular motion something needs to keep accelerating inward. So there is an inward force of some type- say a force from the wall of a spinning spaceship. Now if you’re standing on that wall, and it’s pressing inward on your feet, it feels just like you are standing on a floor. On earth, a floor pushes up on your feet with a force that just balances gravity, which pulls down.  In the spinning spaceship, if you release a ball it will travel in a straight line until it hits the wall. It looks to you like it started accelerating toward the wall, just as a ball you drop in a gravitational field would do. So overall, if you ask what it feels like to be in this spinning spaceship, it’s very similar to being in a gravitational field pointing out toward the outer wall.

Mike W.

(published on 12/27/2007)