Gravity

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)

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

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

Gravity

All planets have their own “g” units.

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.

Force of Gravity cont. What will the force be of a drop of rain falling to the earth with a mass of .0007kg? F = .0007 kg x 9.8 m/s/s .00686 kg*m/s/s (N) Can actually think of it as F=mg This is actually weight.

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!

Obey the Law