K.E. and P.E. in a Pendulum and Spring

[Haseeb Ali]

Can anyone explain the conversion of K.E and P.E during compression and expansion of spring and during the motion of pendulum ?

 

[CWatters]

Start with the pendulum. Which bit don't you understand? Do you know what PE and KE are?

 

[Haseeb Ali]

Start with the pendulum. Which bit don't you understand? Do you know what PE and KE are?

Yes .. i know that. I just want you to explain the interconversion of K.E and P.E as pendulum moves to and fro ,

 

[russ_watters]

We're not going to do that. We require our members to put more effort than that into their own learning.

 

[CWatters]

At maximum deflection the bob has maximum Potential Energy. Call that PE_max.

Using Basic trig. you can calculate the bob height and hence the PE at any angle of deflection. Let's call that PE(theta) where theta is the instantaneous angle of deflection.

Then applying conservation of energy...

PE(theta) + KE(theta) = PE_max
or rearrange that to give
KE(theta) = PE_max - PE(theta)

Edit: Sorry russ_watters is right. That's why I haven't calculated PE(theta) for you.