# Potential Energy and Conservation Energy.

rock_star

## Homework Statement

Suppose the pendulum bob in the figure has a mass of 0.33 Kg and is moving to the right at point B with a speed of 2.4 m/s . Air resistance is negligible.

The diagram is given here :
http://session.masteringphysics.com/prob… [Broken]

I calculated the bob's kinetic energy at point B which is 0.95 J.

Can anyone help me out with following two questions?

At some point the bob will come to rest momentarily. Without doing an additional calculation, determine the change in the system's gravitational potential energy between point B and the point where the bob comes to rest.

I got 0.95 J for the potential Energy for this..

1. Find the maximum angle the string makes with the vertical as the bob swings back and forth. Ignore air resistance.

## Homework Equations

Kinetic Energy = 1/2 mv^2
Potential Energy is = mgh

## The Attempt at a Solution

The bob comes to momentary rest at point A which has largest P.E.
For the first question, I think I have to find P.E between point A and B. So I solved it now and got it right...

Second question.. I am completely clueless.. Can anyone please give me any hints???

Can anyone please explain it and help me out?

Thanks a lot before hand!

I solved the whole thing

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## Answers and Replies

Staff Emeritus
Hint: Use conservation of energy. K.E.+P.E. = constant