Weight of object below the Earth's surface

[rrosa522]

Homework Statement

Calculate the gravitational force acting on a 9.6-kg mass...?
1.5 x 10^4 m above Earth's center. How do i solve this??

Homework Equations

The Attempt at a Solution

the answer is 17N but i don't understand how

 

[NascentOxygen]

Hi rrosa522. http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif

What is the equation for gravitational force between m1 and m2 spaced a distance r apart? If not in your textbook, use google.

 

[SteamKing]

This chap Isaac Newton had stuff like this figured out.

 

[_N3WTON_]

This chap Isaac Newton had stuff like this figured out.

i must admit that after reading this threads title i was disappointed by its content XD

 

[_N3WTON_]

try and use this equation:
$F_{grav} = \frac{Gm_{1}m_{2}}{r^2}$
Where m1 and m2 are two masses, r is a distance and G is a constant

 

[rrosa522]

try and use this equation:
$F_{grav} = \frac{Gm_{1}m_{2}}{r^2}$
Where m1 and m2 are two masses, r is a distance and G is a constant

i tried the formula but i don't get 17N

 

[_N3WTON_]

i tried the formula but i don't get 17N

you should have the mass of Earth (its probably in your textbook) we can call this m1, the other mass is given to you. You have the distance of the object, so enter these values into the formula given above

 

[_N3WTON_]

Better yet, show me what you are entering in the formula

 

[gneill]

A distance of 1.5 x 10^4 m from the Earth's center is well below the Earth's surface, and within the inner core. How did you apply Newton's gravitational force law for that location? Show your work.

Where did your answer of 17N come from ?

Also, your thread title does not meet Physics Forums requirements; thread titles should be descriptive of the thread content, describing the problem or area of physics involved. Please note this for future questions that you post. I have changed the title to be more appropriate.

 

[_N3WTON_]

I'm sorry, I read the problem as 1.5x10^4 from the Earth's surface...either way show how you are using the formula

 

[rrosa522]

i tried the formula but i don't get 17N

I'm sorry, I read the problem as 1.5x10^4 from the Earth's surface...either way show how you are using the formula

(6.67x10^-11) (9.6) (5.97 x 10^24) /
(1.5 x 10^4)^2
the answer i get 1.70x10^7 N
(sorry i didnt add units in my solution, its just gets confusing for me)
the answer at the the back of my textbook is 17 N, i don't understand why

 

[rrosa522]

A distance of 1.5 x 10^4 m from the Earth's center is well below the Earth's surface, and within the inner core. How did you apply Newton's gravitational force law for that location? Show your work.

Where did your answer of 17N come from ?

Also, your thread title does not meet Physics Forums requirements; thread titles should be descriptive of the thread content, describing the problem or area of physics involved. Please note this for future questions that you post. I have changed the title to be more appropriate.

(6.67x10^-11) (9.6) (5.97 x 10^24) /
(1.5 x 10^4)^2
the answer i get 1.70x10^7 N
the answer at the the back of my textbook is 17 N, i don't understand why

 

[gneill]

The textbook is wrong if the radius that you specified is correct.

17 N would be correct if the given radius was in km not meters. That would place the 9.6 kg object well above the Earth's surface. Check the units on the given radius.

 

[hafiz ns]

let take one object as Earth and other as the object
there distance as 1.5 x 10^4
f=gM1m2/d^2

 

[physicsisfunfightme]

you are using meters and kilometres. This is not giving correct answer due to this reason. Use either kilometres or metres only. to make the switch easy go from (1.5x10^4KM) to (1500x10^4M)

 

[SammyS]

you are using meters and kilometres. This is not giving correct answer due to this reason. Use either kilometres or metres only. to make the switch easy go from (1.5x10^4KM) to (1500x10^4M)

Hello, @physicsisfunfightme .



The thread you replied to is more than 7 years old.