# Gravitational Potential

1. Mar 23, 2006

### Harmony

Question:
Calculate the gain of gravitational potential energy of a satelite of mass 200kg between launching and when it is in orbit at a height of 1.2 * 10^6m
above the earth's surface. (R=6.4*10^6)

I approach this question using the equation V=-GM/r . Since the mass of Earth is not given here, I assume it is 6*10^24.

So, I calculate the gravitational potential at the Earth's surface and at 1.2*10^6 m and find the difference. I get the answer of 1.9*10^9.

But the actual answer is 1.7*10^6.

2. Mar 23, 2006

### finchie_88

The gravitational potential is defined as $$V = \frac{GM}{r}$$, while the gravitational potential energy is defined as $$E = \frac{GMm}{r}$$. Although, you must have made a mistake in putting the numbers in aswell.

3. Mar 23, 2006

### andrevdh

I get the same answer as you with the formula
$$V=-\frac{GMm}{r}$$
maybe the given answer is incorrect.