Anyone good at physics?

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SePPii

SePPii

Dovii
MFK Member
May 21, 2011
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Chesapeake, OH
Was given a Take home test struggling on some kinetic energy questions. Can anyone help?


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Ok well like here's an example of the questions I have.

A 2kg pendulum hanging at the end of a 2m chain has potential energy equal to zero. I swing the pendulum through 90 degrees, and hold it. What is the potential energy at 90 degrees?

Then the next question asks me how much work does it take to reach the new potential energy?

Then it says, if I take 5 seconds to move the pendulum , how much power did I use?

Then, what is the maximum velocity reached during te swing of the pendulum?

Sorry to ask so much but these are the only ones I have left in the test and I missed this chapter because I was in the hospital and I have NO idea.


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Hello; So far the subject of your post is much too broad. Can you be more specific about the types of kinetic/potentian energy problems?
 
Lets do one at a time here. Potential energy is PE=mgh, muliply the mass times the gravitational constant times the height of the object above zero. The mass is said to have PE of zero while at the bottom of the string right, therefore that is your lowest point and can be treated as h=0. if it is lifted up to 90degrees, you have to figure out how high upthe mass now is to calctulate the change in potential energy
 
The amount of work is just the amount of energy used to put the mass in its new place. If its not moving at the zero point or the new height, work done for motion is zero, so you are left with work being equal to the change in PE
 
I dont want to go any further until I'm sure that made sense to you. If you have questions about what I said have at it
 
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