The Gravitational Force and the distance from the earth

Click For Summary

Homework Help Overview

The discussion revolves around determining the altitudes above the Earth's surface where the gravitational field strength is reduced to two-thirds and one-third of its value at the surface. The subject area is gravitational forces and field strength, specifically in the context of physics problems involving distance and force equations.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss the use of the gravitational force equation, F=Gm1m2/r^2, and explore how to set up equations to find the required altitudes. Some participants express uncertainty about how to derive the distances for the altitudes, while others suggest using ratios of forces to approach the problem.

Discussion Status

The discussion is ongoing, with participants attempting to clarify the relationship between gravitational force and distance. Some guidance has been offered regarding the setup of equations and the use of ratios, but there is no explicit consensus on the next steps or solutions.

Contextual Notes

Participants note the importance of understanding the relationship between the gravitational force at different distances and the need to derive the altitude from the surface to the specified points above it. There is an acknowledgment of the hint provided in the original problem statement.

Kaze105
Messages
8
Reaction score
0

Homework Statement


Find the altitudes above the Earth's surface where Earth's gravitational field strength would be (a) two-thirds and (b) one-third of its value at the surface. [Hint: First find the radius for each situation; then recall that the altitude is the distance from the surface to a point above the surface.]


Homework Equations



I do believe i use F=Gm1m2/r^2

The Attempt at a Solution



Well, actually I am at a little loss for this question..
 
Physics news on Phys.org
Kaze105 said:

Homework Statement


Find the altitudes above the Earth's surface where Earth's gravitational field strength would be (a) two-thirds and (b) one-third of its value at the surface. [Hint: First find the radius for each situation; then recall that the altitude is the distance from the surface to a point above the surface.]

Homework Equations



I do believe i use F=Gm1m2/r^2

The Attempt at a Solution



Well, actually I am at a little loss for this question..

The hint tells it all.

Set 1 equation = F, another to 2/3 F another to 1/3 F.

Solve by dividing one equation by another.
 
That's the right equation.

Let's say at the surface we have

Fo=G m1 m2/ro^2

and we want to find the distance r1 where the force F1 is

<br /> \frac{F1}{Fo} = \mbox{?} = 2/3<br />

p.s.
Welcome to Physics Forums!
 
problem is that, it doenst give me the distance for the altitude...
 
Yes, that distance is what we are trying to figure out.

As you said, F=Gm1m2/r^2 . Can you use that equation to express the ratio of two forces,

F1 / F0

where F1 is the force at distance r1, and F0 is the force at distance r0?
 

Similar threads

  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 5 ·
Replies
5
Views
6K
Replies
10
Views
4K
  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 28 ·
Replies
28
Views
2K
Replies
2
Views
1K
  • · Replies 10 ·
Replies
10
Views
2K
Replies
3
Views
2K
  • · Replies 7 ·
Replies
7
Views
3K