Chapter 1 Section 4 Gravity: A Force of Attraction p. 20 – 25 NOTES
Vocabulary/Main Ideas
Details and Supporting Facts
o Gravity
o A force of attraction between
objects that is due to their masses.
o Gravity can change the motion of an
object by changing its speed,
direction, or both.
o The Effect of Gravity on
Matter
o All matter is affected by gravity.
o All objects experience an attraction
to all other objects.
o The Size of Earth’s
Gravitational Force
o Earth has a huge mass, so its
gravitational force is very large.
o In order to lift an object, you must
apply enough force to overcome
Earth’s gravity.
o Newton and the Study of
Gravity
o Sir Isaac Newton realized that the
same unbalanced force affected the
motions of a falling apple and the
moon.
o Newton called this force gravity and
summarized his ideas by forming the
law of universal gravitation.
o The Law of Universal
Gravitation
o All objects in the universe attract
each other through gravitational
force.
o The size of the force depends on the
masses of the objects and the
distance between the objects.
**Gravitational force increases as
mass increases
-Since the moon has less mass than
Earth does, the gravitational force
on the moon is 1/6 that of the Earth.
**Gravitational forces decreases as
distance increases
Pictures and Diagrams
Chapter 1 Section 4 Gravity: A Force of Attraction p. 20 – 25 NOTES
Weight
as a Measure of
Gravitational Force
The Differences Between
Weight and Mass
o A measure of the gravitational force
on an object.
o Weight changes as gravitational
force changes
o The amount of matter in an object.
o An object’s mass DOES NOT
CHANGE
o Mass and weight are constant on
Earth, but weight can change
depending on where you are in the
universe.
Units of Weight and Mass
o Weight is measured in Newtons (N)
o Mass is measured in kilograms (kg),
grams (g) and milligrams (mg)
o On Earth, a 100 gram object weighs
about 1 Newton