[Physics for AF.org users]
Newton's law of gravity goes something like this:
F = G (M.m)/r^2
where 'M' is the mass of one of the bodies, 'm' is the mass of the other body, 'r' is the distance between the center of the two bodies and G is the universal constant of gravity: 6.673 84E-11 m3 kg-1 s-2
If you approximate 'r' to the radius of the planet, 'R' (this assumes you're working at sea level and never go far beyond that, so that the approximation R+h ~= R stands, remember, R~=6371km, so I guess this works well for h < 10km and approximately well for h<100km).
So, we have:
F = G M.m/R^2
Let's put in there Earth's mass, Radius and the constant, and put the second objects mass as the first element:
F = m * 6.673 84E-11 * 5.97219E24/ 6371000^2 = m * 9.82
And that gives us the famous: F = m.g
At 10km distance from sea level, g = 9.79 m.kg.s-2
At 100km from sea level, g = 9.52 m.kg.s-2
I hope this puts to rest some of everyone's troubles.
Newton's law of gravity goes something like this:
F = G (M.m)/r^2
where 'M' is the mass of one of the bodies, 'm' is the mass of the other body, 'r' is the distance between the center of the two bodies and G is the universal constant of gravity: 6.673 84E-11 m3 kg-1 s-2
If you approximate 'r' to the radius of the planet, 'R' (this assumes you're working at sea level and never go far beyond that, so that the approximation R+h ~= R stands, remember, R~=6371km, so I guess this works well for h < 10km and approximately well for h<100km).
So, we have:
F = G M.m/R^2
Let's put in there Earth's mass, Radius and the constant, and put the second objects mass as the first element:
F = m * 6.673 84E-11 * 5.97219E24/ 6371000^2 = m * 9.82
And that gives us the famous: F = m.g
At 10km distance from sea level, g = 9.79 m.kg.s-2
At 100km from sea level, g = 9.52 m.kg.s-2
I hope this puts to rest some of everyone's troubles.
