Calculations associated with a bouncing ball

[annamae]

Homework Statement

For our final project we have to design a lab, take the data, and write a lab report. My lab is bouncing balls of different masses, onto different surfaces, from different heights, and use balls of different materials in order to see what factor influences efficiency the most. I am now onto the calculation section and not sure of what equations would be relevant or if I'm even doing them right.

Homework Equations

PE1 x 100
PEinitial

KE = mg(h0-h1)

KE = ½mv2
mg(h0-h1) = ½mv2

The Attempt at a Solution

1. PE1 x 100
PEinitial

mgh1 x 100
mghinitial

(.18)(9.8)(.68) x 100
(.18)(9.8)(1)

68% - the amount of potential energy retained after impact

2. KE = mg(h0-h1)
KE = (.18)(9.8)(1-.68)
KE = .56448 J

a measurement of the joules that the ball has at the top of the second bounce

3. KE = ½mv2
mg(h0-h1) = ½mv2
(.18)(9.8)(1-.68) = ½(.18)v2
.56448 = .009v2
7.919 m/s = v

a measure of velocity when the ball is dropped

 

[AlexChandler]

Its a bit hard to follow your equations.

If you want to find the energy lost after one bounce it will be:

\Delta E = mg (h_i - h_f)

For the percent energy lost, it is

\frac{E_i - \Delta E}{E_i}

Is this what you were trying to do?

It is unclear what measurements you have made. I am assuming you measured initial height, and final height after one bounce. If so, these calculations would be the correct ones.

Try to learn to use LaTeX. It is quite easy. Here is a link that will help you learn it.

https://www.physicsforums.com/showthread.php?t=8997