# Mass of Pulley help

1. Jan 26, 2005

### theknownothing

Hi people again, sorry to not have done extensive searching in the forum for a problem like this but I need some help ASAP.

By means of a rope whose mass is negligible, two blocks are suspended over a pulley, as the drawing shows. The pulley can be treated as a uniform solid cylindrical disk. The downward acceleration of the 44.0 kg block is observed to be exactly one-half the acceleration due to gravity. Noting that the tension in the rope is not the same on each side of the pulley, find the mass of the pulley.

Thank you guys!

#### Attached Files:

• ###### pulley.jpg
File size:
6.5 KB
Views:
184
Last edited: Jan 27, 2005
2. Jan 27, 2005

### theknownothing

I am not sure which formula to use to find the mass of the pulley since the accelartion is

a=m2-m1/m1+m2 * gravity that would give me the accel if it was a massless pulley.

any help appreciated.

3. Jan 27, 2005

### vincentchan

I can't see your graph... but i think i can guess how its look like
since you are new here, just wanna let you know our rule here does not allow me giving you the full solution..... I can only give you some hints and you gotta work out the problem yourself

hints:
1. what is the touqe acting on the pulley?
2. what is the angular accelation for the pulley
3. after you have the above numbers and the rotational inertial for a disk, you should able to figure out what the mass is...

4. Jan 27, 2005

### theknownothing

alright thanks got the problem!!