Question

(a) Determine the amount of work (in joules) that must be done on a 104 kg payload to elevate it to a height of 993 km above the Earth's surface.
______ MJ


(b) Determine the amount of additional work that is required to put the payload into circular orbit at this elevation.

_____J

I have absolutley no idea how to find this problem, and it is also not in our book. If anybody has any idea, can you please help!!!

THANKS!! :)

It is in your book, the concept is energy. Potential energy is mgh. That answers a.

In b, you have to add the Kinetic energy

at orbit, centripetal force equals gravitational force.

mv^2/R= GMe*m/distance^2
1/2 mv^2= 1/2 GMe*m/distance^2
where distance is radiusEarth+ heightgiven.

Answer 1

Potential Energy = -GMemobject[(1/rb)-(1/ra)]

a) = -GMm[(1/2Re)-(1/Re)]


b) -GMm[(1/(Re+999000)-(1/Re)] =
X joules
X joules/1000000 = X Milijoules

c) I have no idea.... I think it should be (Orbital energy - X joules) but this is giving me the wrong answer for some reason...
Orbital Energy = -GMm/(2(Re+999000))
I get a wrong answer even if I switch signs...