JEE Main202523 Jan 2025Evening ShiftPhysicsRotational MotionActual
A circular disk of radius R meter and mass M kg is rotating around the axis perpendicular to the disk. An external torque is applied to the disk such that (t)=5 t^2-8 t , where (t) is the angular position of the rotating disc as a function of time t . How much power is delivered by the applied torque, when t=2 ~s ?
Options
- A72 MR ^2
- B8 MR ^2
- C108 MR ^2
- D60 MR ^2
Correct answer
D. 60 MR ^2
Step-by-step solution
aligned & =5 t ^2-8 t & = d dt =10 t -8 & = d dt =10 & p = & =( I ) & = ( mR ^2 2 ) & = ( mR ^2 2 )(10)(10 aligned Put t =2 p =60 mR ^2