A hook of radius 2m weighs 100 kg. It rolls along a horizontal floor so that its centre of mass has a speed of 20cm/s. How much work has to be done to stop it?
Answer & explanation
Correct answer: option 2
vcm = 20 cm/s = 0.20 ms
Work required to stop the hoop = Rotational kinetic energy + Translational kinetic energy
Work required = 12 Iω2+12Mv2cm = 4 J.