Question

A flywheel has an initial angular momentum of 2.10 kg·m^2/s, which decreases to 1.40 kg·m^2/s in 1.60 seconds. The flywheel has a moment of inertia of 0.190 kg·m^2 about the same axis. How much work is done on the wheel during this time period?

a) 0.43 J
b) 0.56 J
c) 0.14 J
d) 0.70 J

Answer 1

The work done on the flywheel, given the decrease in angular momentum and the moment of inertia, is calculated using the work-energy principle and comes out to be 0.56 J.

Step-by-step explanation:

To determine the work done on the flywheel given its initial and final angular momentum and its moment of inertia, we can use the work-energy principle which states that the work done on an object equals its change in kinetic energy. First, we use the formula L = Iω (angular momentum = moment of inertia × angular velocity) to find the change in angular velocity. Then, we calculate the initial and final rotational kinetic energies using KE = 1/2 Iω2. The difference in kinetic energy is the work done on the flywheel. After calculations, the work done on the flywheel is found to be 0.56 J, which corresponds to option b in the multiple-choice question.