I've got to find things out about these pendulums

[thear]

Homework Statement

The pendulum is started swinging from a height of 0.3000 m above its rest position and allowed to swing freely back and forth. If 1.00% of the bob's energy is lost due to friction each swing, to what maximum height will the bob swing at the end of its fourth swing?

Homework Equations

I cannot even begin to think of any

The Attempt at a Solution

h=0.3000m
energy lost=1.00%/swing
max h=?

PEi + KEi = PEf + KEf + HE

 

[berkeman]

Homework Statement

The pendulum is started swinging from a height of 0.3000 m above its rest position and allowed to swing freely back and forth. If 1.00% of the bob's energy is lost due to friction each swing, to what maximum height will the bob swing at the end of its fourth swing?

Homework Equations

I cannot even begin to think of any

The Attempt at a Solution

h=0.3000m
energy lost=1.00%/swing
max h=?

PEi + KEi = PEf + KEf + HE

Welcome to the PF.

What is the equation for the PE of the pendulum as a function of height? What is the initial PE? What is the PE after the 1st swing? After the 2nd, after the 3rd, after the 4th? And so what is the height after the 4th swing?

Try talking problems like this through, and you will be able to at least show an attempt at a solution when you post the problems here...