Pulleys, Force, and Acceleration

[Sevenheartz]

Homework Statement

Set up a pulley system and place two masses at rest. Give a quick tug on one mass, setting the system in motion. After release, does the system accelerate of move at a (relatively) constant velocity? Does it make sense?

Question #2
Now substitute a heaver mass for one of your masses. Move the heavier mass up to the top of the pulley. When you release the mass, measure the distance it travels (1m) and the time it takes. Repeat for three trials. Based on your results, calculate the average acceleration of the heavier mass? How would the acceleration of the lighter mass compare?

Homework Equations

The Attempt at a Solution

Okay, for the first one.. I'm just confused. When I did the lab, it looked like it moved at a relative constant velocity, but I'm not sure how to explain that. I also saw someone write down it was accelerating... so I was confused. If anyone can help me out here (just theory works), then it would be of great help.

For the second one, I also just want to clarify - I have the distance (which is 1m for all three trials), and the times (Which I averaged out). Do I simply do d/t to find the average velocity, then divide that by time to find acceleration?

Also, instead of putting it a new thread (unless I have to?) - the only purpose of the string in the pulley system is to change the direction, correct?

I know this may be a bit much, but I just need this clarified. Thanks a lot.

 

[anathema]

Hello,

In response to the first question, the system will accelerate at first due to the initial tug on one mass. However, once the system reaches a steady state, it will move at a relatively constant velocity. This makes sense because the initial tug provides an unbalanced force, causing the system to accelerate. Once the system reaches a steady state, the forces on both masses are balanced and there is no net force, resulting in constant velocity.

For the second question, you are correct in your approach. You can calculate the average acceleration of the heavier mass by dividing the distance (1m) by the average time it takes for the mass to travel that distance. This will give you the average velocity, and then dividing by time again will give you the average acceleration.

And yes, the string in the pulley system is used to change the direction of the forces acting on the masses. It does not add or subtract any significant force to the system.

I hope this helps clarify things for you. Good luck with your lab!

 

[baba89]

I can provide some insights and clarifications on the concepts of pulleys, force, and acceleration.

Firstly, when you set up a pulley system and place two masses at rest, the system will initially be at rest as there is no net force acting on it. When you give a quick tug on one mass, you are applying a force to the system, causing it to accelerate. This acceleration happens because the force you applied is greater than the force of friction and other resistive forces acting on the system. Once you release the mass, the system will continue to move at a relatively constant velocity. This is because the force of friction and other resistive forces will eventually balance out the force you applied, resulting in a constant velocity. So, it makes sense that the system moves at a relatively constant velocity after the initial acceleration.

Now, when you substitute a heavier mass for one of the masses in the pulley system, the system's acceleration will change. This is because the heavier mass has a greater inertia (resistance to change in motion) compared to the lighter mass. When you release the heavier mass from the top of the pulley, it will accelerate at a slower rate compared to the lighter mass. This is because it takes more force to overcome the greater inertia of the heavier mass. To calculate the average acceleration of the heavier mass, you can use the equation a = Δv/Δt, where Δv is the change in velocity and Δt is the change in time. You can use the distance and time data from your experiments to calculate the average acceleration of the heavier mass.

In terms of the string in the pulley system, its main purpose is to change the direction of the force applied. This allows you to lift a heavier mass with less force by spreading the force over a larger distance. The string also helps to keep the masses in place and prevent them from slipping off the pulley.

I hope this helps clarify some of your questions. Keep up the good work with your experiments and keep asking questions to deepen your understanding!