Impossible escape velocity question

In summary, the question asks for the escape velocity of a hypothetical celestial object with the same density as the sun. However, it is not possible to find the escape velocity with only the information given (density). The formula for escape velocity is v = 8.873 x 10^-4 x r, but without knowing the radius of the object, the actual velocity cannot be determined. Additionally, the escape velocity depends on the mass, not the density, so the question is flawed.
  • #1
infirmus
6
0
I've got a question in front of me that asks to find the escape velocity for a hypothetical celestial object that has the same density as the sun.

MC answers are -
1)2.51 x 10^3 m/s
2)6.18 x 10^5 m/s
3)3.08 x 10^5 m/s
4)5.42 x 10^10 m/s

As far as I can work out its not possible to find an escape velocity while only knowing the density. I can work out that

v = 8.873 x 10^-4 x r

but not find actual v without knowing the radius.
 
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  • #2
You are right. The "escape velocity" depends upon the mass not the density.

If you are not given the radius of the object as well as the density, you cannot find the mass.
 
  • #3
infirmus said:
I've got a question in front of me that asks to find the escape velocity for a hypothetical celestial object that has the same density as the sun.

This is a silly question (on their part). If they want you to also assume that it has the same radius as the sun, and you do need a radius to solve this problem, then answer is B. If that is what they want, though, they might as well have asked what the escape velocity from the surface of the sun was.
 

What is escape velocity?

Escape velocity is the minimum speed an object needs to reach in order to break free from the gravitational pull of a larger body. It is typically measured in meters per second.

What is the escape velocity of Earth?

The escape velocity of Earth is approximately 11.2 kilometers per second. This means that any object traveling at this speed or faster can escape Earth's gravitational pull and enter into orbit around the planet.

Can escape velocity be achieved on Earth?

Technically, yes, but it is extremely difficult and requires a tremendous amount of energy. The only way to achieve escape velocity on Earth is through a rocket or spacecraft with powerful engines.

What happens if an object does not reach escape velocity?

If an object does not reach escape velocity, it will remain in orbit around the larger body. This is why planets and moons are able to stay in orbit around the sun or larger planets.

Is escape velocity the same for all objects?

No, the escape velocity varies depending on the mass and size of the larger body. For example, the escape velocity of the moon is much lower than that of Earth due to its smaller size and mass.

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