Chapter 3: Forces
Date:____________
Section 2.1: Gravity - Notes
Learning Goals:
 Describe gravitational force.
 Distinguish between mass and weight.
Gravity:
 Gravity: an ______________________________ force between _______________________ objects
o
Depends on the __________________ of the objects and the ________________________
between them

Your book is _____________________________ to exert a force you can feel, but it is
too ____________________.

Jupiter is _______________________________ to exert a noticeable force, but it is
too _____________________.

The Earth is ______________________________ and __________________________
to exert a noticeable force.
The Law of Universal Gravitation:

Newton’s equation enables the force of gravity to be calculated between any two objects if their
_________________________ and the ____________________________ between them is known.


F=
o
G=
o
m1 =
o
m2 =
o
d=
As the distance between two objects ______________________________, the gravitational force
between them ______________________________.

No matter how far apart two objects are, the gravitational force never completely goes to _________!
Earth’s Gravitational Acceleration:

Close to the Earth’s surface, the acceleration of an object in free fall is __________________.
o
Free fall ignores _____________________ except gravity!

This acceleration constant is sometimes labeled ______.

Using Newton’s 2nd Law of Motion, the force of Earth’s gravity on a falling object is
o

F=

F=

m=

g=
Example: What is the gravitational force on a sky diver with a mass of 600 kg?
Weight:

Even if you aren’t _________________, the force of Earth’s gravity is still pulling you downward.

Weight: the ____________________________________________ exerted on an object

Weight can be calculated by the following equation:
o

W=
Weight and mass ______________________________________________!
o
Weight is a measure of __________________, mass is the measure of the amount of
_______________________ in an object.
o

Weight _______________ as gravity changes; mass _________________.
Example: A person on Earth has a mass of 54 kg, what is their weight?