Find translational Ke Rotational Ke

[blackout85]

Homework Statement

A basketball weighs 500grams or (.5 kg) it has a radius of 10cm (.10 m) and is rolling at 2.0 m/s. Find translational Ke Rotational Ke Translational momentum and Rotational momentum.

Homework Equations

translational ke= 1/2mv^2
rotational ke = 1/2Iw^2 ( I am unsure of what inertia equation to use for a basketball)
Translational momentum= mv^2
rotational ke = iw

The Attempt at a Solution

Translational ke = 1/2 mv^2= .5(.5kg)(2.0m/s)^2= 1 J
I think I know how to do the equations I just don't know what equation to use for the rotational inertia for a basketball, if someone could help me on that. Thanks

 

[Andrew Mason]

Homework Statement

A basketball weighs 500grams or (.5 kg) it has a radius of 10cm (.10 m) and is rolling at 2.0 m/s. Find translational Ke Rotational Ke Translational momentum and Rotational momentum.

Homework Equations

translational ke= 1/2mv^2
rotational ke = 1/2Iw^2 ( I am unsure of what inertia equation to use for a basketball)
Translational momentum= mv^2
rotational ke = iw

I think you mean L = angular momentum = I\omega

The Attempt at a Solution

Translational ke = 1/2 mv^2= .5(.5kg)(2.0m/s)^2= 1 J
I think I know how to do the equations I just don't know what equation to use for the rotational inertia for a basketball, if someone could help me on that.

The moment of inertia of a solid or hollow sphere is a calculus problem. It works out to \frac{2}{5}MR^2 for a solid sphere and \frac{2}{3}MR^2 for a hollow sphere (see the http://hyperphysics.phy-astr.gsu.edu/hbase/mi.html#cmi"). Which one would you use?

How do you determine the rotational speed from the translational speed? ie. how long does it take the ball to roll 360 degrees or 2\pi radians?

AM

 

[radou]

This should serve as a clue: http://www.physics.upenn.edu/courses/gladney/mathphys/java/sect4/subsubsection4_1_4_3.html" .

Edit: oops, late.