How much work needs to be done to lift a 250 kg satellite to an altitude of 300,000m 2. Relevant equations I am confused on this as to whether I should use the equation W=mgh Do I input the value of G as 9.81? Or do I use the formula g= GM/r^2 to find the gravity at 300,000 m and input it into the equation 3. The attempt at a solution I tried to do this question but I can't get the answer at the back of the book which is 7.04 * 10^ 8 So this is what I did 6.67*10^-11*5.97*10^24*250/6678000^2 =8.9 Then 6678000*8.9*250 =1.5 *10^10 Also tried to use the gravitational potential energy equation which apparently our teacher says gives the same answer as w=mgh 6.67*5.97*10^-11*10^24*250/6678000 =1.5*10^10 None of my ways work to give 7.04*10^8 . Please I really really need help.