What is the acceleration of a falling block attached to a pulley system?

In summary, the problem involves a 2 kg block resting on a table with a coefficient of friction of 0.75. A string attached to the block passes over a pulley and is connected to a 4 kg block. The pulley is a 0.5 kg uniform disk with a radius of 15 cm. As the 4 kg block falls, the string does not slip on the pulley. The question is, what is the acceleration of the 4 kg block and what is the tension in the string above and below the pulley? Using the equations for frictional force and Newton's second law, the acceleration is found to be 3.9 m/s². However, calculating the tension in the string
  • #1
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Homework Statement


A block of mass m1 = 2 kg rests on a table with which it has a coefficient of friction µ = 0.75. A string attached to the block passes over a pulley to a block of mass m3 = 4 kg. The pulley is a uniform disk of mass m2 = 0.5 kg and radius 15 cm. As the mass m3 falls, the string does not slip on the pulley.
With what acceleration does m3 fall?

Homework Equations


Frictional Force = mew x normal
F = MA
Newtons' second law

The Attempt at a Solution


If I could treat the pulley as a point and didn't have to pay attention to it this would be a cinch. To be honest, I don't know what to do with it at all, and I'm looking for some conceptual help here.
 
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  • #2
Much time later, I finally got the acceleration to be 3.9. The next question in this set is: what is the tension in the string above the table, and below the pulley. (They will be separate.)
Now, since F=MA, I thought this would be easy. 3.9 x 4 = 15.6. It itsn't that easy, it turns out. Any ideas?
 
  • #3
Well, 15.6 N is the net force on the 4 kg mass.

This force is due to the string tension and what else?
 

1. What is a "Two Blocks and a Pulley" experiment?

A "Two Blocks and a Pulley" experiment is a basic physics experiment that involves two blocks connected by a rope or cable and a pulley. The pulley is a simple machine that helps to change the direction of the applied force and allows for the movement of the blocks.

2. What is the purpose of a "Two Blocks and a Pulley" experiment?

The purpose of this experiment is to demonstrate the concept of mechanical advantage, which is the ability to use a simple machine like a pulley to make work easier. It also helps to illustrate the principles of force, friction, and motion.

3. How does a "Two Blocks and a Pulley" experiment work?

In this experiment, one block is attached to a fixed surface and the other block is attached to a rope that runs over the pulley. When a force is applied to one end of the rope, the block connected to the other end will move in the opposite direction due to the pulley. The experiment can be modified by changing the weight of the blocks or the number of pulleys to observe the effects on the system.

4. What can be learned from a "Two Blocks and a Pulley" experiment?

By conducting this experiment, one can learn about the concept of mechanical advantage, which is the ratio of output force to input force in a system. It also helps to understand how simple machines like pulleys can reduce the amount of force needed to move an object. Additionally, the experiment can demonstrate the relationship between force, friction, and motion.

5. What are the real-world applications of a "Two Blocks and a Pulley" experiment?

The principles learned from this experiment can be applied to real-world scenarios, such as understanding how elevators and cranes work. It can also be helpful in designing and improving machinery and equipment that utilize pulleys and other simple machines. Additionally, it can be used to explain concepts in engineering, physics, and other related fields.

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