# G calculation

1. Jun 16, 2010

### Kat007

1. The problem statement, all variables and given/known data
I am wondering how did the local graviational field (free fall acceleration) g = 9.81m/s^2 is calculated?

2. Relevant equations

3. The attempt at a solution
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Jun 16, 2010

### kuruman

It is usually calculated by assuming that the Earth is a perfect sphere and then by using Newton's law of universal gravitation to find the force on an object at the surface of the Earth. Input parameters are the gravitational constant and the radius and mass of the Earth.

3. Jun 16, 2010

### Kat007

So what is the actual equation used to obtain the g (with the values)?
Just out of general interest.

4. Jun 16, 2010

### kuruman

$$G\frac{M_E\:m}{R_E^2}=mg$$

Solve for g.

5. Jun 16, 2010

### Kat007

OK thank you for your time.
:)