A uniform brass disc of radius a and mass m is set into spinning with angular speed `omega_0` about an axis passing through centre of disc and perpendicular to the palne of disc. If its temperature increases from `theta_1^@C` to `theta_2^@C` with out disturbing the disc, what will be its new angular speed ?

Options

A. `omega_(0)[bot+2a(theta_(2)-theta_(1))]`
B. `omega_(0)[bot+a(theta_(2)-theta_(1))]`
C. `(omega_(0))/([bot+2a(theta_(2)-theta_(1))])`
D. None of these

Answer

C

Explanation

`I_(1)W_(1)=I_(2)W_(2)or, mr_(1)^(2)W_(1)=mr_(2)^(2)W_(2)or, W_(2)=(r_(1)^(2))/(r_(2)^(2))W_(1)=(r_(1)^(2)W_(0))/(r_(2)^(2)(1+2alphaDeltaalpha))=(W_(0))/((1+2alphaDeltatheta))`