A grind-stone is in the form of a solid cylinder has a radius of 0.5 m and a mass 50 kg. What torque will bring it from rest to an angular velocity of 300 rev/min in 10 s ? What is the kinetic energy when it is rotating at 300 rev/min ?

Explanation

To solve the problem step by step, we will find the torque required to bring the grindstone from rest to an angular velocity of 300 revolutions per minute (rev/min) in 10 seconds, and then calculate the kinetic energy when it is rotating at that speed.

### Step 1: Convert Angular Velocity to Radians per Second
The first step is to convert the angular velocity from revolutions per minute to radians per second.

1. **Given:** Angular velocity in rev/min = 300 rev/min
2. **Conversion factor:** 1 revolution = \(2\pi\) radians and 1 minute = 60 seconds.

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