Why won't my equation work for this pully system?

In summary: In particular, show your work in applying the equation you quoted above.In summary, the problem involves two objects of known mass being connected by a string over a frictionless pulley. The tension in the string is equal to the mass multiplied by gravity. The task is to find the accelerations of the objects and the tensions in each section of the string. Using the equation T2R-T1R = I x (angular acceleration), the angular acceleration can be found by knowing the inertia. This can then be used to find the acceleration of the masses by multiplying it by the radius. However, the solution may not be correct and more detail is needed to determine the error.
  • #1
LarryJ
5
0

Homework Statement


Two objects, of masses m1 = 485.0 g and m2 = 494.7 g, are connected by a string of negligible mass that passes over a pulley with frictionless bearings. The pulley is a uniform 53.0-g disk with a radius of 4.08 cm. The string does not slip on the pulley.
Find the accelerations of the objects.
Find the tensions of each area of the string between the masses and the pully.

Homework Equations


T2R-T1R = I x (angular acceleration)
Tension is found by mass x gravity

The Attempt at a Solution


If I can solve for the angular acceleration by knowing the inertia, then I should be able to find the acceleration of the masses by multiplying the angular acceleration by the radius. But I keep getting the wrong answer. What am I doing wrong?
 
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  • #2
LarryJ said:

Homework Statement


Two objects, of masses m1 = 485.0 g and m2 = 494.7 g, are connected by a string of negligible mass that passes over a pulley with frictionless bearings. The pulley is a uniform 53.0-g disk with a radius of 4.08 cm. The string does not slip on the pulley.
Find the accelerations of the objects.
Find the tensions of each area of the string between the masses and the pully.

Homework Equations


T2R-T1R = I x (angular acceleration)
Tension is found by mass x gravity

The Attempt at a Solution


If I can solve for the angular acceleration by knowing the inertia, then I should be able to find the acceleration of the masses by multiplying the angular acceleration by the radius. But I keep getting the wrong answer. What am I doing wrong?
Hello LarryJ. Welcome to PF !

It will be much easy to help you, if you show considerably more detail regarding your method of solution.
 

Related to Why won't my equation work for this pully system?

1. Why is my equation not giving me the correct result for this pulley system?

There could be a few reasons why your equation is not working. One possibility is that you are using the wrong formula or not accounting for all the variables in the system. Another possibility is that your measurements or input values are inaccurate. It is also possible that there is an error in your calculations or equations. It may be helpful to double check your work and make sure all factors are accounted for.

2. Can I use the same equation for different pulley systems?

It depends on the type of pulley system you are using. Some pulley systems, such as simple and compound pulleys, have specific equations that can be used for any system of that type. However, more complex pulley systems, such as block and tackle or differential pulleys, may require different equations. It is important to understand the specific pulley system you are working with and use the appropriate equation.

3. How do I know which variables to include in my equation for a pulley system?

The variables you include in your equation will depend on the type of pulley system you are working with and the information you have about the system. Generally, you will need to know the mass of the object being lifted, the number and type of pulleys, and the force being applied to the system. It is important to carefully analyze the pulley system and identify all the relevant variables before creating an equation.

4. Can I simplify my equation for a pulley system?

In some cases, it may be possible to simplify your equation for a pulley system. This could be done by using different formulas or by combining multiple equations into one. However, it is important to make sure that your simplified equation still accurately reflects the physics of the system and provides an accurate result. It may be helpful to consult with a colleague or do further research to determine if simplification is appropriate.

5. Why is my equation not working for a real-life pulley system?

Real-life pulley systems may have factors that are difficult to account for in equations, such as friction or imperfectly balanced loads. This can lead to discrepancies between predicted and actual results. It is important to remember that equations are simplified models of real-world situations and may not always perfectly reflect the complexities of a system. In these cases, it may be necessary to adjust the equation or account for these factors in other ways, such as through experimentation or using a different equation altogether.

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