Answer to Question #160133 in Field Theory for Onel

Question

How much kinetic energy must a 100 kg spacecraft have at the surface of the earth to the earth to be able to leave the earth completely?
Explain what will happen if the space craft had (i) Less energy (ii) More energy

Answer 1

$$K=G\frac{mM}{R}\\K=(6.67\cdot10^{-11})\frac{(100)(5.97\cdot10^{24})}{(6.37\cdot10^{6})}=6.25\cdot10^{9}J$$

i) The craft will rotate around the Earth.

ii) It will move with constant speed from the Earth.