Gravity earth's radius question

In summary, gravity is a force that exists between objects with mass and is responsible for keeping objects in orbit and for the weight of objects on Earth. The Earth's radius is the distance from its center to its surface, and it does not directly affect the strength of gravity. Objects fall towards the Earth's center due to the gravitational pull created by the Earth's mass. While the Earth's radius does change over time, these changes occur over long periods and are due to geological processes.
  • #1
physicshard22
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Homework Statement


The force of gravity on an astronaut is 600N at the Earth's surface. what is the force of gravity acting on him at a distance of 10 times the Earth's radius?



Homework Equations


F = Fm1m2/r^2


The Attempt at a Solution


F = Gm1m2/r^2
F = 600/11r^2
F = 4.96N

11r because its measured from the surface of the earth
 
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  • #2
I think it means at a distance of 10 times R from the centre of the Earth. (not from the surface)
 
  • #3
to the astronaut, which is 10 times the Earth's radius, plus the radius of the Earth itself.This is incorrect. The correct approach to solving this problem would be to use the equation F = Gm1m2/r^2, where G is the gravitational constant (6.67x10^-11 Nm^2/kg^2), m1 is the mass of the astronaut (which we can assume to be 80 kg), m2 is the mass of the Earth (5.97x10^24 kg), and r is the distance from the center of the Earth to the astronaut (11 times the Earth's radius, or 11x6.37x10^6 m). Plugging in these values, we get:

F = (6.67x10^-11 Nm^2/kg^2)(80 kg)(5.97x10^24 kg)/(11x6.37x10^6 m)^2
F = 5.37x10^5 N

Therefore, the force of gravity acting on the astronaut at a distance of 10 times the Earth's radius is 5.37x10^5 N, significantly higher than the force of 600N at the Earth's surface. This is because the force of gravity decreases with distance according to the inverse square law.
 

What is gravity?

Gravity is a fundamental force that exists between all objects with mass. It is responsible for keeping objects in orbit around each other and for the weight of objects on Earth.

What is the Earth's radius?

The Earth's radius is the distance from the center of the Earth to its surface. It is approximately 6,371 kilometers or 3,959 miles.

How does the Earth's radius affect gravity?

The Earth's radius does not directly affect the strength of gravity. However, as you move away from the center of the Earth, the force of gravity decreases due to the increasing distance between objects.

Why do objects fall towards the Earth's center?

Objects fall towards the Earth's center due to the force of gravity. The Earth's mass creates a gravitational pull that attracts all objects towards its center.

Does the Earth's radius change over time?

The Earth's radius does change over time, but the changes are very small and occur over long periods of time. The Earth's radius can change due to geological processes such as tectonic plate movement and erosion.

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