Science Buddies: "Ask an Expert"

Did the experiment it was a sucess, would like to draw a simple diagram of what happened, Have a diagram with the direction of how the cups were spun also show the centripetal force arrow moving towards the center of the circle. Would I show gravitational fore opposing the centirpetal force. Would they be cancelling each other out allowing for the cup to continue on the path?

Would gravitational force be moving from the center of the circle our.
Would the gravitational force for lack of a better word be our arm and the string that connects the cup .

If this string broke we could say the forces were not equal therefore the gravitational force/ or would it be acceleration was too high .Once the tangent to the circle or grav force became too much the string would break and the cup would then continue on in a straight line.


Just need to explain this better as the teachers in the school cannot. Sad, I know that is why I need your help. Hoope you can help me out.

thanks Donna Brochez BC,CANADA

Hi,
I think that this following website might help you:

http://hyperphysics.phy-astr.gsu.edu/hbase/cf.html

This is the same concept as suspending a mass on a string and rotating about a circle. Let us know if you have more questions!

still confused, the marble moved to the outside of the circle. Should it have not moved to the center of the circle. How do the marbles movement demonstrate Centripetal force. Did the experiment 2 times 3 reps each same result. The science fair judges said the marble should have moved towards the center of the circle, is the experiment missing an explanation

I'm having a hard time visulizing what you actually did, so I have no clue how to help you. Is there a good description of your experiment somewhere that you can point us to?