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.