Trouble with potential energy

In summary, potential energy is the stored energy an object possesses due to its position. It is the object's capability to do work, but it is not actively doing work at the moment. This energy is typically converted to kinetic energy through the force of gravity. The stored energy is released when the object is allowed to move or change positions.
  • #1
9huyna1
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Hi everybody, I'm reviewing for the MCAT (it's been a while), and I'm having a lot of trouble understanding potential energy.

In my review book (and a whole bunch of other googled sources), it defines energy as the capability to do work.
It also says work is something along the lines of, the transfer of energy.

On Wikipedia, I read that potential energy is the energy associated with an object due to its position.
So...putting it all together, potential energy is the capability of an object to do work due to its position.

I understand that the potential energy got there by doing work on the object, bringing it to its present position.
From what I understand, this potential energy is transferred to kinetic energy due to the gravitational force.

What I don't understand is... The definition says the potential energy is the object's ability to do work How is it doing work?

I thought the work (conversion of potential energy to kinetic energy) was due the gravitational force acting on the object.

Did I totally miss the point of all of this?

P.S. I forgot to mention (although I think it's similar for other types), I'm asking about gravitational potential energy.

Thank you in advanced.

Just a quick edit: I was wondering why the definition couldn't be something like:
Gravitational potential energy is the object's capability to have work done on it by gravity?
 
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  • #2
That's why it is called potential rather than actual energy. The energy is 'stored' if you will until some action releases or converts it. If, for example, you compress a spring and then latch it so that it cannot expand, then the compressed spring contains some quantity of potential energy, which will remain stored as long as the latch is secure. Once the latch is released, then this stored energy will be converted into kinetic energy as the spring expands.
 
  • #3
The definition says the potential energy is the object's ability to do work How is it doing work?

It's not doing work. It has the potential to do work.

You have the ability to pass a test but you're not actually taking a test at the moment.

Water held back behind a dam has potential energy. It's only converted to actual energy when allowed to flow through a turbine.
 
  • #4
Thank you for your responses, I think I get it now.
 
  • #5


Hi there,

I can understand your confusion about potential energy. However, let me try to clarify a few things for you.

Firstly, you are correct in understanding that potential energy is the energy an object possesses due to its position. This means that if an object is in a position where it can potentially do work, it has potential energy. This energy is not actively doing work, but rather it has the potential to do work if certain conditions are met.

Now, let's look at your example of gravitational potential energy. When an object is lifted to a certain height, it has potential energy because it is now in a position where it can potentially do work (such as falling and doing work on the ground or on another object). This potential energy is not actively doing work, but it can be converted into kinetic energy (the energy of motion) when the object is allowed to fall.

You are correct in understanding that the work (conversion of potential energy to kinetic energy) is due to the gravitational force acting on the object. The gravitational force is constantly acting on the object and as it falls, this force is doing work on the object, converting its potential energy into kinetic energy.

To sum it up, potential energy is the energy an object has due to its position, and it can be converted into kinetic energy when certain conditions are met. The work done on the object is due to the force acting on it, and this force is what converts potential energy into kinetic energy.

I hope this helps clear up any confusion you had about potential energy. Keep up the good work with your MCAT review!
 

1. What is potential energy?

Potential energy is the energy an object possesses due to its position or configuration. It is the stored energy that has the potential to do work in the future.

2. How is potential energy different from kinetic energy?

Potential energy is the energy an object has due to its position, whereas kinetic energy is the energy an object has due to its motion. Potential energy can be converted into kinetic energy and vice versa.

3. What are some examples of potential energy?

Some examples of potential energy include a stretched rubber band, a book on a shelf, a rollercoaster at the top of a hill, and a ball at the top of a hill. In each of these situations, the object has the potential to do work if released or allowed to move.

4. How is potential energy calculated?

The formula for potential energy is PE = mgh, where m is the mass of the object, g is the acceleration due to gravity, and h is the height of the object. The unit for potential energy is joules (J).

5. Can potential energy be negative?

Yes, potential energy can be negative. This occurs when the reference point for measuring potential energy is taken to be at a higher point than the actual position of the object. Negative potential energy indicates that the object is in a lower position than the reference point and has the potential to do work as it moves back up to the reference point.

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