a flywheel has a moment of inertia of 2.3 kg*m^2.

What is the average power needed to spin it up from rest to an angular velocity of 70 rad/s. in 30 seconds

Question

a flywheel has a moment of inertia of 2.3 kg*m^2.

What is the average power needed to spin it up from rest to an angular velocity of 70 rad/s. in 30 seconds

anonymous · Answer

As you should have learned previously, the translational kinetic energy equation is

$$K=(1/2)mv^2$$
Similarly, rotational kinetic energy is

$$K=(1/2)Iv^2$$
Where I is your moment of inertia.

$$K=(1/2)(2.3 kg*m^2)(70 rad/s)=80.5J$$
This is the work that must be done (we are not dealing with potential energy, solely kinetic). Now, solve for power using

$$P=W/t$$