Astronaut weight

nazz

An astronaut weighs 1000N at the surface of the earth of radius 6500 km, what his weight will be at 13000 km and 19500km from the centre of the earth?

Do I have to calculate the new value of g at 13000 km using the following?

(G• Mearth) / (Rearth)2
Where:
G = 6.673 x 10-11 N m2/kg2
Mass of the earth = (5.98 x 1024 kg)

New Re = 13000 km (converted to m)

Then W = M x g

Is there another way of solving it?

Filip Larsen

You can calculate the answer without knowing the values G and M (or GM). Try write up the equation for the weight W₁ at radius R₁ and the weight W₂ at radius R₂ using GM as you did above and then look at the ratio W₁/W₂.

nazz

Great answer Filip, thanks