Potential energy of a massive string

In summary, the potential energy of a string of mass m and length L with a block of mass M attached to it can be found by considering the masses of the string and the block as well as their respective distances from the ground. The length of the string will also come into play when calculating the total potential energy. The specific details of the setup, such as whether the string is hanging vertically or horizontally, if there is a mass on the end or middle, and if the string is swinging or acting like a spring, will also impact the calculation of potential energy.
  • #1
JCOM44
How can I find the potential energy of a string of mass m and length L that has a block of mass M attached to it?
The string is uniform, so I know its center of mass is at L/2.
 
Physics news on Phys.org
  • #2
JCOM44 said:
How can I find the potential energy of a string of mass m and length L that has a block of mass M attached to it?
The string is uniform, so I know its center of mass is at L/2.
How would you find the potential energy of just the string?
 
  • #3
phinds said:
How would you find the potential energy of just the string?
I tried using the fact that the only force on the string is F=mg, then W=mg*y, and remembering that -∇U=W, I found that U=-½mgy^2, but I feel this is not right because it has no information about the length, am I doing something wrong?
 
  • #4
JCOM44 said:
I tried using the fact that the only force on the string is F=mg, then W=mg*y, and remembering that -∇U=W, I found that U=-½mgy^2, but I feel this is not right because it has no information about the length, am I doing something wrong?
Potential energy is defined with respect to some reference height. You have the masses of the rope and the weight, so you have two centers of mass to sum for the total GPE. But each has to be some distance above the ground (if that's where you are taking GPE=0 to be), so when you do that sum, the length of the rope will come into play. Makes sense?
 
  • Like
Likes Chestermiller
  • #5
JCOM44 said:
How can I find the potential energy of a string of mass m and length L that has a block of mass M attached to it? The string is uniform, so I know its center of mass is at L/2.

More details required. Is the string hanging vertically? horizontally? Mass on the end? middle?

Is the string swinging back and forth like a pendulum?

Is the string acting like a spring?
 

Related to Potential energy of a massive string

1. What is potential energy of a massive string?

Potential energy of a massive string refers to the stored energy in a string that is under tension or stretched.

2. How is potential energy of a massive string calculated?

The potential energy of a massive string is calculated using the formula PE = ½kx², where k is the string's stiffness coefficient and x is the displacement of the string from its equilibrium position.

3. What factors affect the potential energy of a massive string?

The potential energy of a massive string is affected by two main factors: the stiffness of the string (determined by the material and thickness) and the displacement of the string from its equilibrium position.

4. Can potential energy of a massive string be converted into other forms of energy?

Yes, potential energy of a massive string can be converted into other forms of energy, such as kinetic energy, when the string is released and the stored energy is released as motion.

5. How does the potential energy of a massive string relate to work?

The potential energy of a massive string is directly related to the work done on the string. Work is done on the string when it is stretched or compressed, increasing its potential energy. When the string is released, the potential energy is converted into work and the string returns to its equilibrium position.

Similar threads

Replies
11
Views
840
Replies
4
Views
1K
Replies
5
Views
822
Replies
2
Views
134
Replies
12
Views
2K
Replies
8
Views
1K
Replies
2
Views
835
Replies
6
Views
1K
Replies
34
Views
2K
Back
Top