# Homework Help: Help needed on Energy

1. Jun 29, 2010

### tgpnlyt7095

Physics Question regarding Work ( calculations of kinetic energy & potential energy )

A Pendulum of mass 0.7kg is swinging . The maximum speed of the pendulum, where the
pendulum's position is at it's lowest, is 2.0ms-1. Calculate the maximum kinetic energy of
the pendulum and the maximum gravitational potential energy of the pendulum as it is at its greatest height.

ok, youre understood, sorry yea first time using this ;x

Relevant equations:
Ek ( Kinetic Energy ) = 1/2mv²
Ep ( Potential Energy ) = mgh

The Attempted Solution :

Ek = 1/2mv²
= 1/2 x 0.7 x 2²
= 1.4J

Ep = m x g x h
= ( 0.7 kg ) x 10m/s² ( i shall do a round-up ) x h ( unknown )

i was stucked here as i cant get the value of 'h' o.o

Last edited: Jun 29, 2010
2. Jun 29, 2010

### kuruman

Hi tgpnlyt7095 and welcome to PF. Please follow the rules of this forum and use the template when you seek help with homework. Show us the relevant equations and tell us what you tried and what you think about the problem. We just don't give answers away.

3. Jun 29, 2010

### JWSiow

I'm not sure if my answer's correct, but I'd say the max. potential energy is the same as the max. kinetic energy because of the Law of the Conservation of Energy. ALL of the potential energy should be converted to kinetic energy, hence the max. kinetic energy = max. potential energy.