# Homework Help: What are gravitational units?

1. Jan 16, 2012

### Rakinniya

What are gravitational units??

My teacher recently taught us about gravitational units.... she said that its the absolute unit multiplied by acceleration due to gravity.... I did not understand the significance of this...Please help me

2. Jan 16, 2012

### bacon

Re: What are gravitational units??

I have never heard of "gravitational units", but based on your second phrase, "… she said that its the absolute unit multiplied by acceleration due to gravity…", I would guess that she is referring to what is commonly called "G's"; as in , " The astronauts experienced 4 G's during their blastoff."
Assuming this is what she meant, then this is an expression of force in terms of the force due to gravity at sea level on earth.
If you stand on earth at sea level, the force on you is F=mg where g is the acceleration due to gravity at sea level on earth(i.e. 9.8 m/s^2).
If you next were to stand on another planets surface where you felt two times the force of gravity you felt on earth then the equation could look like
F=2mg=m2g
so that you weigh twice what you did on earth, hence you feel 2"G's".
So the general rule is when you are given the number of "G's" you multiply that times the acceleration g(9.8m/s^2) to find the force.
F=m(#G's)g.
Hope this helps.
(note:The G used here is NOT the gravitational constant)

3. Jan 17, 2012

### Rakinniya

Re: What are gravitational units??

tnx that was quite helpful.... but em not sure if she meant the same thing... ..I can't find nything in my text book .today...she asked us. "what is the gravitational unit of momentum?".....Theres an article on .....Gravitational metric system in wikipedia...... Looks like its an outdated one.....anyway thanks!!