Two masses connected by a string uniform circular motion. HELP

In summary, two masses, m1 and m2, are connected by a string and are in uniform circular motion on a frictionless, horizontal table. The tension in the string is equal to the centripetal force required to keep m1 in circular motion, which is given by m1v^2/R. This force is provided by the weight of m2, which is equal to m2 x g. Both expressions for tension are correct and are a result of Newton's third law. However, when solving for tension, only the variables and symbols given in the question can be used.
  • #1
MelissaJL
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Two masses connected by a string uniform circular motion. HELP! :)

Homework Statement


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A puck of mass m1 is tied to a string and allowed to revolve in a circle of radius R on a frictionless, horizontal table. The other end of the string passes through a small hole in the center of the table, and an object of mass m2 is tied to it. The suspended object remains in equilibrium while the puck on the tabletop revolves.

What is the tension in the string? (Use any variable or symbol stated above along with the following necessary: g.)

So. I keep looking at this problem...there's more questions to this but the first part is stopping me from completing the others. I was wondering how does the mass m2 effect the tension in the string if it is stationary? I know the tension for mass m1 by itself would simply be T=m1v2/R. Also that if I isolated mass m2 the tension would simply be T=m2g. How do I incorporate them or is one case null? Any suggestions? Thank you :)
 
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  • #2


You have it sorted out!
The tension needed to keep m1 in circular motion is m1v^2/R. This is the centripetal force.
This force is provided by the WEIGHT of m2 =m2 x g.
Think of Newton's 3rd law. If the string is pulling on m1 with a force F then the string must be pulling on m2 with a force F. (remember there is no friction to worry about)
 
  • #3


You got it - both expressions have to be correct.
However, one of them uses a variable or symbol not supplied and you are restricted by the terms of the question to use only those which are supplied.
 

1. What is uniform circular motion?

Uniform circular motion is a type of motion in which an object moves in a circular path at a constant speed. This means that the object's velocity remains constant in magnitude but changes in direction as it moves along the circular path.

2. How are two masses connected by a string in uniform circular motion?

In uniform circular motion, two masses are connected by a string when one mass is attached to the end of the string and the other mass is held by the string at a fixed distance from the first mass. The string allows the two masses to move in a circular path while maintaining a constant distance.

3. What is the role of centripetal force in uniform circular motion?

Centripetal force is the force that acts towards the center of a circular path and keeps an object moving in a circular motion. In the case of two masses connected by a string, the tension in the string acts as the centripetal force.

4. What is the relationship between the speed of the masses and the radius of the circular path in uniform circular motion?

The speed of the masses in uniform circular motion is directly proportional to the radius of the circular path. This means that as the radius increases, the speed of the masses also increases, and vice versa.

5. How does the mass of the objects affect uniform circular motion?

The mass of the objects does not affect the uniform circular motion as long as the tension in the string remains constant. This is because the centripetal force is determined by the speed and radius of the circular path, not the mass of the objects.

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