Help with physics impulse problem

[Arden]

I just need a little help getting past the first step. I have already converted rpm to rad/sec.

120 J are done on a fly wheel to raise its speed from 60rpm to 160 rpm. Find its moment of inertia.


How do I convert 120J to power

and how do I set up the inertia half

 

[whozum]

Think in terms of angular kinetic energy.

 

[thepatientmental]

To convert 120J to power, you need to divide the energy (Joules) by the time it takes to do the work. In this case, the time is not given, so we cannot calculate the power. However, we can solve for the moment of inertia using the given information.

To set up the inertia half, you need to use the formula for impulse: impulse = change in momentum. In this case, the impulse is equal to the work done on the flywheel, which is 120J. The change in momentum can be calculated using the formula: change in momentum = mass x change in velocity. Since the mass of the flywheel is not given, we can use the formula for rotational inertia, which is equal to mass x radius^2. So, the formula becomes: impulse = mass x radius^2 x change in angular velocity.

Now, we can substitute the given values: 120J = mass x radius^2 x (160rpm - 60rpm) converted to rad/s. Since you have already converted the rpm to rad/s, you can simply plug in the values and solve for the moment of inertia.

I = (120J) / (radius^2 x change in angular velocity)

I hope this helps you move past the first step and solve the problem. Remember to always double check your units and make sure they are consistent throughout the calculation. Good luck!