Question

How can we determine the weight of the Earth?

Answer 1

weight? or mass?

Answer 2

earth is floating in space where everythings weightless :)

Answer 3

Sorry. Mass.

Answer 4

I forget all the details, but its something Newton made up i believe :)

http://www.astro.washington.edu/courses/labs/clearinghouse/labs/MassEarth/massearth.pdf

Answer 5

My physics teacher gave me some funny formulas

Answer 6

F = Gmm/r^2?

Answer 7

This calculation is done using Newton's Law of Gravity, which formulates the attractive force (gravitational force) that two masses exert on each other:

F=GmM/r2

In Newton's equation, F is the gravitational force, G is a constant of proportionality, M and m are the two masses exerting the forces, and r is the distance between the two objects.
G was calculated by Henry Cavendish in 1798, and was determined to be 6.67 x 10-11 m3/(kg sec2).
Also needed is Newton's second law of motion, F=ma, where F is the force applied to an object, m is the mass of the object, and a is its acceleration due to the force.
Galileo determined that the acceleration due to the force of gravity of Earth was a constant equal to 9.8 m/sec2 near the surface of the Earth.
Lastly, you need to know the radius of the Earth; this was first calculated by the Greek Eratosthenes thousands of years ago (by comparing shadows in wells during the summer solstice about 230 B.C.).

Answer 8

1. F = GmM/r^2 = ma, where F is the gravitational force, G is the gravitational constant, M is the mass of the Earth, r is the radius of the Earth, and m is the mass of another object (near the surface of the Earth).

2. since F=ma, => GmM/r^2 = ma
GM/r^2= a (The m's canceled out.) Now solve for M, the mass of the Earth.

3. M = ar^2/G, where a = 9.8m/sec^2, r = 6.4 x 106m, and G = 6.67 x 10-11m3/(kg sec2).

4. M = 9.8 x (6.4 x 106)2/(6.67 x 10-11) = 6.0 x 1024 kg

Answer 9

I knew it was Newtons fault; just couldnt be happy the earth was big, had to go and measure it ;)

Answer 10

he was a MAN after all and just wanted to COMPARE SIZES !!!!!!!! :))))))

Answer 11

knowing the radius and acceleration he used the the equation:\[g =Gm/r^2\]