Chapter 10.5, Problem 10.5QQ

You turn off your electric drill and find that the time interval for the rotating bit to come to rest due to frictional torque in the drill is Δt. You replace the bit with a larger one that results in a doubling of the moment of inertia of the drill’s entire rotating mechanism. When this larger bit is rotated at the same angular speed as the first and the drill is turned off, the frictional torque remains the same as that for the previous situation. What is the time interval for this second bit to come to rest? (a) 4Δt (b) 2Δt (c) Δt (d) 0.5Δt (e) 0.25Δt (f) impossible to determine