Hi All,(adsbygoogle = window.adsbygoogle || []).push({});

I'm trying to figure out how to model a rolling ball in the x y plane.

I've started with the basic equation of motion with constant acceleration

d = v[tex]_{}0[/tex]t + 1/2at[tex]^{}2[/tex]

v[tex]_{}0[/tex] is the initial velocity

a is acceleration

t is time

Assume that v is a vector at an angle [tex]\alpha[/tex] with the x axis.

If the plane is flat, a is is all due to the force of rolling resistance F[tex]_{}r[/tex]. I represent F[tex]_{}r[/tex] as a vector in the opposite direction to v. Is this the correct way to treat rolling resistance? If so, does this mean that if we decompose the equation into x and y components, does this mean that F[tex]_{}r[/tex] should be decomposed into x and y components?

F[tex]_{}rx[/tex] = F[tex]_{}r[/tex]sin[tex]\alpha[/tex]

and

F[tex]_{}ry[/tex] = F[tex]_{}r[/tex]cos[tex]\alpha[/tex]

Given that I'm treating F as a vector it makes sense to do this, but it doesn't feel right to me. This means that the rolling resistance varies in x and y with the angle of the vector v.

Is this right? Also, is F independent of the speed of the ball?

Sorry about the appearance. The subscripts aren't working for some reason. Only the t squared should show as a superscript. the rest should be subscripts.

Thanks for any help you can give.

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Rolling Ball

**Physics Forums | Science Articles, Homework Help, Discussion**