## A community for students. Sign up today

Here's the question you clicked on:

## adnanchowdhury 3 years ago Kinetic Energy and Potential Energy question: http://d.pr/i/vcK4 The gymnast descends from position B and regains contact with the trampoline when it is in its unstretched position. At this position, her centre of mass is 3.2 m below its position at B. Calculate her kinetic energy at the instant she touches the unstretched trampoline

• This Question is Closed
1. timo86m

mass*4.2*9.8 I think

2. timo86m

mass is 55

3. adnanchowdhury

nope. That's PE of when the person is at B.

4. timo86m

and i will be ke once the person reaches back

5. timo86m

|dw:1337888965008:dw|

6. timo86m

|dw:1337889467795:dw|

7. timo86m

|dw:1337889552978:dw|

8. lalaly

kinetic energy =3.2/4.2 *2264

9. stormfire1

@lalaly: Wow...that's much more shorter than the stuff I was about to post but it's dead-on.

10. stormfire1

Well, almost :) (3.2/4.2)*2264

11. stormfire1

At any rate, what lalaly did was calculate the total PE from point A to B given 4.2m, 55kg and g (mgh = 2264J). Her KE at point B will be equal to this. Once you know those two things, you should be able to see that (3.2/4.2)*2264J will be the amount of KE at the point where the girl just touches the unstretched trampoline.

#### Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy