Transcript Gravityx

Gravity
Bellringer
In your notebook write a paragraph on :
Significantly decreased gravity
gives astronauts the sensation of being
weightless and forces astronauts to
make many adjustments in their
activities. Write a paragraph explaining
what you would like and dislike about
living with reduced gravity.
Gravity Objectives
• Describe gravity and its effect on matter.
• Explain the law of universal gravitation.
• Describe the difference between mass and weight.
Gravity
Gravity is a force of attraction between
objects that is due to their masses.
Gravity occurs between any two objects
that have mass
All matter has mass, and gravity is a
result of mass.
Therefore, all matter is affected by gravity
and all objects experience an attraction
toward all other objects.
Gravity and Newton
• The Core of an Idea Why do objects fall toward the
Earth? What keeps the planets moving in the sky?
• In 1665, British scientist
Sir Isaac Newton made the
connection between these
two questions when, as
legend has it, he saw an
apple falling from a tree.
Earth’s Gravity
Earth’s gravity pulls you toward the
center of Earth with an acceleration of
9.8m/s2.
Anytime you want to move something you
off the ground you have to overcome the
force of gravity
Something to Remember
The mass of an object never changes
when moved, however; the weight of
an object is dependent on the force of
gravity.
Gravity as an unbalance force
• Newton knew that unbalanced forces
are needed to change the motion of
objects.
• He reasoned that an unbalanced force
on the moon kept the moon moving
around the Earth.
• He proposed that these two forces are
actually the same force––gravity.
Law of Universal Gravitation
• Part 1: Gravitational Force Increases as Mass
Increases
• Gravitational force is small between objects that
have small masses. Gravitational force is large
when the mass of one or both objects is large.
• Part 2: Gravitational Force Decreases as
Distance Increases
• Gravitational force is strong when distance
between two objects is small. If the distance
between two objects increases, the gravitational
force pulling them together decreases rapidly.
Weight as a Measure of
Gravitational Force
• The Differences Between Weight and Mass
•Weight is related to mass, but they are not the
same.
• Weight is a measure of the gravitational force on an
object.
•Weight changes whenever gravitational force
changes.
• Mass is the amount of matter in an object.
•An object’s mass does not change if gravitational
force changes.
Think Pair Share
How can you calculate your mass?
How can you change your weight?