A solid disk (moment of inertia = 20 [kg⋅m2][kg⋅m2]) rotates around an axle (with friction) connected to a device capable of reading the total energy at any given point in time. At point 1 the total energy is 250 [J] and point 2 the total energy is 160 [J]. If the speeds at point 1 and point 2 are 3 [rad/s] and 4 [rad/s], respectively, how much work is done by the non-conservative forces in this system?

A solid disk (moment of inertia = 20 [kg⋅m2][kg⋅m2]) rotates around an axle (with friction) connected to a device capable of reading the total energy at any given point in time. At point 1 the total energy is 250 [J] and point 2 the total energy is 160 [J]. If the speeds at point 1 and point 2 are 3 [rad/s] and 4 [rad/s], respectively, how much work is done by the non-conservative forces in this system?