What is the energy requirement for traveling from Earth to the Moon?

  • Thread starter Thread starter msattar07
  • Start date Start date
  • Tags Tags
    Earth Moon Power
AI Thread Summary
The energy required to travel from Earth to the Moon is greater than the energy needed to return, as indicated by the gravitational forces at play. The gravitational pull of Earth is stronger, necessitating more energy to escape its influence. Conversely, traveling back to Earth involves a decrease in potential energy. The discussion highlights the importance of understanding gravitational potential energy differences in space travel. Overall, the consensus is that it takes more energy to launch from Earth to the Moon than to return.
msattar07
Messages
10
Reaction score
0

Homework Statement


The amount of energy required to get a spacecraft from the Earth to the Moon

a. is greater than the energy required to go from the Moon to Earth.
b. is the same as the energy required to go from the Moon to Earth.
c. is less than the energy required to go from the Moon to Earth.


Homework Equations



G= mM/r^2

The Attempt at a Solution


I think the answer is c.
 
Physics news on Phys.org
Why?
 
wait, i get it now.

gravitational force is greater on Earth so it would require MORe energy to go from Earth to moon..
answer is A.
 
Yes. Though you are oversimplifying a bit. In going from the Earth to the moon means you are losing energy to the potential energy of the Earth's gravitational field and gaining it from the moon's. Coming back is the reverse. Which potential energy difference is greater?
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top