Two masses suspended from a pulley

In summary, the conversation is about a physics problem involving two masses connected by a string and suspended from a pulley. The system starts from rest and the string does not slip on the pulley. The problem asks for the acceleration of the larger mass and the tensions on each side of the pulley. The equations provided by the student are not completely correct and they are asked to show their work and provide separate equations for each mass.
  • #1
rusticle
4
0

Homework Statement



hi, I am really stuck on this question:

Two masses m and M, M>m are joined by a massless inelastic string and suspended from a pulley of radius R and moment of inertia I. the pulley rotates about its centre freely with no friction. The system starts at t=0 from rest. during the motion of the system, the string does not slip on the pulley's rim.


Homework Equations



a) Find the acceleration of M. What sort of motion is produced?
b)Are the tensions on each side of the pulley the same? Do they vary with time? Find their magnitude(s) in terms of M, m, I and g.



The Attempt at a Solution



i have produced a free body diagram and come up with the following equations:

ma + Ma = mg + Mg - [T][/m] - [T][/M] (1)

Newton II (rotational ver) I(alpha) = TR (2)

and a = R(alpha)

im not sure where to go next, or if I am correct with these equations.
help would be muchly appreciated
 

Attachments

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  • #2
rusticle said:
i have produced a free body diagram and come up with the following equations:

ma + Ma = mg + Mg - [T][/m] - [T][/M] (1)

Newton II (rotational ver) I(alpha) = TR (2)

and a = R(alpha)
Your equations (1) and (2) are not quite right. Show how you got them. (I suggest writing a separate equation for each mass, so you end up with three equations.)
 

1. How does a pulley affect the motion of two masses suspended from it?

A pulley can change the direction of the force applied to an object and distribute the weight of the masses evenly on both sides. It can also reduce the amount of force needed to move the masses.

2. What is the relationship between the masses and their acceleration in a pulley system?

In a pulley system, the two masses have the same acceleration but in opposite directions. This is because the pulley acts as a pivot point, and the masses are connected by a rope that does not stretch or slip.

3. Can the masses have different weights in a pulley system?

Yes, the masses can have different weights in a pulley system. As long as the pulley is frictionless and the rope is massless, the weight of the masses will not affect their acceleration.

4. How is the tension in the rope related to the masses in a pulley system?

The tension in the rope is equal on both sides of the pulley and is determined by the weight of the masses. The heavier the masses, the greater the tension in the rope.

5. What happens to the acceleration of the masses if the pulley is not frictionless?

If the pulley has friction, it will oppose the motion of the masses and decrease their acceleration. The amount of friction will depend on the type and condition of the pulley, as well as the weight of the masses.

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