- #1
gimak
- 56
- 1
Homework Statement
How to derive W=(.5*I)*((ωf^2)-(ωi^2)) from W=τ*(θ)
Homework Equations
The two equations seen above (big W is work; little w is rotational velocity, τ is torque, alpha=rotational acceleration).
s=r*θ a=r*(alpha) (ωf^2)-(ωo^2)=2*(alpha)*(θ) F=r*τ F=ma
The Attempt at a Solution
W=T*(θ)=(F/r)*(s/r)=(r^-2)*F*s=(r^-2)*ma*s=(r^-2)*m*(r*alpha)((ωf^2)/(2*alpha))*r
=0.5*m*ωf^2
Obviously this isn't right. What went wrong?