A constant force of 50 N is applied tangentially to the rim of a solid disc with a 60 cm radius. The wheel has a moment of inertia of 40 kgm^2.
a) What is the mass of the disc?
b) 4 seconds after starting from rest, what angular speed does it have?
c) How many revolutions does it complete in 4 seconds?
d) Show by calculation that the kinetic energy of the wheel when t = 4 is equal to the work done upon the wheel by the external force from t = 0 to t = 4 seconds.