Calculating Rotational Energy of Disk After Forces Applied

[ctwokay]

Homework Statement

A uniform disk with mass m = 9.32 kg and radius R = 1.37 m lies in the x-y plane and centered at the origin. Three forces act in the +y-direction on the disk: 1) a force 340 N at the edge of the disk on the +x-axis, 2) a force 340 N at the edge of the disk on the –y-axis, and 3) a force 340 N acts at the edge of the disk at an angle θ = 30° above the –x-axis.

Q: If the disk starts from rest, what is the rotational energy of the disk after the forces have been applied for t = 1.5 s?

Homework Equations

I=1/2*mR^2
τ=I*alpha
ω=ωi+alpha*t
E=1/2*I*ω^2

The Attempt at a Solution

I just want to check whether my working is correct or not.

I use ω=ωi+alpha*t which ωi is zero,then i sub in the values to E=1/2*I*ω^2 to find the rotational energy.
Please help me check my workings is it right?
Thank you.

 

[tiny-tim]

hi ctwokay!

(have an alpha: α and try using the X² and X₂ buttons just above the Reply box )

I=1/2*mR^2
τ=I*alpha
ω=ωi+alpha*t
E=1/2*I*ω^2
…
I use ω=ωi+alpha*t which ωi is zero,then i sub in the values to E=1/2*I*ω^2 to find the rotational energy.

yes, that's fine!

 

[ctwokay]

thank you very much