Proving GPE considering 0 at earths surface

  • Thread starter Miraj Kayastha
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In summary, the formula to calculate the GPE (gravitational potential energy) of a mass away from Earth's surface can be derived by using the standard definition for potential and considering the potential at Earth's surface and at the point of interest. The resulting formula is a constant times the difference between the inverse of the distances from the Earth's surface and the point of interest, which can be simplified to mgh by assuming h is much smaller than the radius of the Earth.
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Miraj Kayastha
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Can someone derive the formula to calculate the GPE of a mass which is away from the Earth by considering 0 potential at Earth's surface
 
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##GPE=mgh##
h is 0 at the surface of earth.
 
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Miraj Kayastha said:
Can someone derive the formula to calculate the GPE of a mass which is away from the Earth by considering 0 potential at Earth's surface

Assume a point mass for the Earth. Use the standard definition for potential (this looks like homework so you can easily find it yourself) then write down the potential at the Earth's surface and the Potential for the point of interest. The difference will be the difference.
The answer will be a constant times (1/R1 - 1/R2),
which can be re-written (with R2 - R1 on the top) and then you substitute h = R2 - R1.
Then you assume h << R and then you can eliminate some terms to give mgh. (Where g is the value at the surface)

You can do this!
 

Related to Proving GPE considering 0 at earths surface

1. What is GPE and why is it important to consider 0 at Earth's surface?

GPE stands for gravitational potential energy, which is the potential energy that an object possesses due to its position in a gravitational field. It is important to consider 0 at Earth's surface because it allows us to calculate the change in GPE as an object moves from one point to another, and it also helps us understand the relationship between the height of an object and its potential energy.

2. How is GPE calculated considering 0 at Earth's surface?

The formula for calculating GPE is GPE = mgh, where m is the mass of the object, g is the acceleration due to gravity (9.8 m/s^2 on Earth), and h is the height of the object above Earth's surface. In this formula, h represents the change in height from the reference point, which is considered to be 0 at Earth's surface.

3. Can GPE be negative and what does it mean?

Yes, GPE can be negative if the reference point is taken to be above Earth's surface, such as in outer space. A negative GPE indicates that the object has less potential energy at that point compared to being at the reference point. This means that work would need to be done on the object to bring it back to the reference point.

4. How does the mass of an object affect its GPE?

The mass of an object does not directly affect its GPE. However, a heavier object will have a greater force of gravity acting on it, which will result in a larger change in GPE as it moves from one point to another. This is because the formula for GPE includes the mass of the object.

5. What are some real-life applications of GPE considering 0 at Earth's surface?

GPE is important in many real-life scenarios, such as calculating the potential energy of water in a hydroelectric dam, determining the energy needed for a roller coaster to complete its course, and understanding the energy required for a satellite to maintain its orbit around Earth. GPE is also used in studying the behavior of tides and ocean currents.

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