How to draw a freebody diagram of a non ideal pulley

[Gorz]

Homework Statement

Just a quick question. I am not entirely sure how to draw an FBD of a pulley with Inertia.

Im doing a problem solving excercise for the atwood machine with two masses over a non ideal pulley and need to sketch its FBD.

Thanks

 

[Doc Al]

The important thing to show on a FBD of the pulley are the two rope tensions acting on it, since they are the only forces creating a torque on the pulley (assuming no friction). The key is that each side of the rope will have its own tension, so call them T₁ and T₂.

 

[nlightner]

A freebody diagram is a visual representation of all the forces acting on a body or object. In the case of a non ideal pulley, the diagram would include the forces acting on the pulley itself, as well as the forces acting on the masses attached to it.

To draw a freebody diagram of a non ideal pulley, you would first need to identify all the forces acting on the pulley. These may include the weight of the pulley, the tension in the rope, and any frictional forces.

Next, you would need to determine the direction and magnitude of each force. For example, the weight of the pulley would be directed downwards, while the tension in the rope would be directed upwards. The magnitude of these forces would depend on the mass of the pulley and the masses attached to it, as well as the acceleration of the system.

Additionally, if the pulley has inertia (meaning it has mass and can rotate), you would need to include the rotational forces acting on it, such as torque and angular acceleration.

Once you have identified and determined the direction and magnitude of all the forces, you can draw them as arrows on your freebody diagram, with the direction of the arrow representing the direction of the force and the length of the arrow representing the magnitude of the force.

It is important to note that the freebody diagram is a simplified representation of the forces acting on the pulley, and may not include all the complexities of a real-world system. However, it can still be a useful tool in understanding and solving problems involving non ideal pulleys.