A wheel is mounted on a stationary axle which we can assume frictionless. As a result, the wheel can turn freely but cannot translate. The wheel can be described as two concentric rings of masses 1 kg and 0.5 kg and radii 50 cm and 85 cm. You wrap a string of negligible mass around the outer ring and pull on it, increasing the angular speed of the wheel from 0 to 8 revolutions per second. Determine:
a) How much work is done by you on the pulling;
b) If your hand has moved 3 meters (that is the amount of string that you unwrap in the pulling), how much is the pulling force?.