A small puck moves in a circle on a frictionless air table. The circular motion is enforced by a person holding a string tied to the puck and going through a tiny hole in the middle of the table. Initially, the puck moves in a circle of radius R at speed v. But later the string is pulled down through the hole forcing the puck to move in a smaller circle of radius 1/2 R. How much work did the person do while moving the puck from R to 1/2 R?
1. W =3/4 mv2
2. W =3/2 mv2
3. W = mv2
4. W =5/2 mv2
5. W =2/3 mv2
6. W =1/3 mv2
7. W =4/3 mv2
8. W = 2mv2
9. W =1/4 mv2
10. W =1/2 mv2
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Our tutors have indicated that to solve this problem you will need to apply the Spinning on String of Variable Length concept. You can view video lessons to learn Spinning on String of Variable Length. Or if you need more Spinning on String of Variable Length practice, you can also practice Spinning on String of Variable Length practice problems.
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