Can I Solve This Massive Pulley Problem Without Using Energies?

[isukatphysics69]

Homework Statement

Homework Equations

The Attempt at a Solution

ok so i have derived the equation

T₂-T₁ = .5M_PULLEY*a_tangential
and stopped here because i am missing the mass of the pulley. now since the equation gives a velocity i was thinking to use energy, is this the correct approach?

 

[BvU]

so i have derived the equation

That is very nifty (and probably correcet), but I don't see it if you don't post your working. Especially since you start out from zero relevant equations !

stopped here because i am missing the mass of the pulley

Call it $M_P$ and proceed. Perhaps it divides out

 

[mfb]

and stopped here because i am missing the mass of the pulley.

You can just keep working with M_pulley. But you don't even have to do it.

What is the type of motion mass 2 will make? Do you have to consider details of the pulley system to find its acceleration?

Does the problem later ask to calculate the pulley disk mass? Because it is possible with the given information.

 

[isukatphysics69]

You can just keep working with M_pulley. But you don't even have to do it.

What is the type of motion mass 2 will make? Do you have to consider details of the pulley system to find its acceleration?

Does the problem later ask to calculate the pulley disk mass? Because it is possible with the given information.

Yes the problem later ask me to calculate the disk mass, it is 6:30am I was too tired to type out all of the work I am going to sleep right now but I'm curious why they have velocity I was wondering if I need to consider energy on this problem or not

 

[mfb]

You don't have to consider energies. You can use them to find the disk mass, but you can equally do everything without energies.

For the first step (acceleration) energies are not useful.