1. Gravity

2. Gravity Def: An attractive pulling force between any two objects
Depends on two factors
*Mass of objects
*Distance between objects
(Distance WILL influence “G” more)

3. Mass of objects
If we increase the mass of either object  force of gravity goes UP
If we decrease the mass of either object  force of gravity goes DOWN

4. Distance between objects
If we increase the distance between objects  force of gravity goes DOWN
If we decrease the distance between objects  force of gravity goes UP

5. Gravity

6. All planets have their own “g” units.

7. Calculating with Gravity
Use the same formula F=ma
The acceleration of a falling object near the earth’s surface is around 9.8m/s/s
We can calculate the Force of gravity on an object by using this acceleration and the mass of the object.

8. Force of Gravity cont.
What will the force be of a drop of rain falling to the earth with a mass of .0007kg?
F = kg x 9.8 m/s/s
kg*m/s/s (N)
Can actually think of it as F=mg
This is actually weight.

9. Weight SI units are N or kg*m/s/s Weight and mass are not the same!!
Weight = mass x gravity
Wt = m x g
Weight is a force! Mass is not!

10. Obey the Law