Finding Escape Velocity from a Gravitational Potential Energy Surface

In summary, the conversation discusses finding the expression and value of escape velocity from the surface of an object by considering its gravitational potential energy and using the work energy theorem. The person also mentions the importance of accounting for the nonconstant nature of gravity.
  • #1
imy786
322
0

Homework Statement



By considering the gravitational potential energy of an object at the surface , find an expression for the escape speed from the surface and determine its value.

Homework Equations



GPE= mgh

The Attempt at a Solution



KE= 1/2* m * v^2

GPE= mgh

GPE+ KE = 0

mgh = - 1/2 * m * v^2
gh= - 1/2 * v^2


v^2= -2gh

v= sqare root of (-2gh)

this is the escape velocity...
 
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  • #2
You've computed velocity needed to reach a height h in a uniform gravitational field. Is that the same concept as 'escape velocity'?
 
  • #3
You also appear to be assuming gravitational force is constant. If that were true, there would be no "escape velocity". It is impossible to "escape" a constant force!
 
  • #4
Well if ur looking for escape velocity...it should be[tex]\sqrt{\frac{2GM}{R}}[/tex]
 
  • #5
thanks for the info...
so how shall i start off instead
 
  • #6
you shud use the work energy theorem
 
Last edited:
  • #7
You should change your expression for gravitational potential energy to one appropriate for a nonconstant field.
 
  • #8
Remember that gravity is an "inverse square formula"!
 

What is escape velocity?

Escape velocity is the minimum speed required for an object to break free from the gravitational pull of a celestial body, such as a planet or moon.

What is gravitational potential energy?

Gravitational potential energy is the energy an object possesses due to its position within a gravitational field, such as the Earth's gravitational field.

How is escape velocity calculated?

Escape velocity can be calculated using the equation: Ve = √(2GM/r), where Ve is the escape velocity, G is the gravitational constant, M is the mass of the celestial body, and r is the distance between the object and the center of the celestial body.

What is the significance of escape velocity?

Escape velocity is significant because it determines whether an object can break free from the gravitational pull of a celestial body and enter into orbit or continue on a trajectory into space.

How does the shape of a gravitational potential energy surface affect escape velocity?

The shape of a gravitational potential energy surface affects escape velocity because it determines how much energy an object must have to escape the gravitational pull of the celestial body. A steeper potential energy surface requires a higher escape velocity, while a shallower surface requires a lower escape velocity.

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