The Law of Gravity

Newton's Law of Gravity

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The Law of Gravity

You may have heard a story about Isaac Newton coming up with the idea of gravity when an apple fell out of a tree and hit him in the head. The story isn’t true, but seeing how things like apples fall to Earth helped Newton form his ideas about gravity, the force of attraction between things that have mass.

Multiple Choice

When Newton saw how things like apples fall to Earth helped him form his ideas about gravity. Gravity is the force of...

• ...attraction between things that have mass

• ...of attraction or repulsion that arises between electrically charged particles because of their motion

• ...of attraction or repulsion between two charged particles

Mrs.C| Science

The Law of Gravity (SC.6.P.13.2)

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Of course, people had known about the effects of gravity for thousands of years before Newton came along. After all, they constantly experienced gravity in their daily lives. They observed over and over again that things always fall toward the ground.

Open Ended

Give an example of how you have experienced gravity in your daily life.

The Law of Gravity (SC.6.P.13.2)

However, it wasn’t until Newton developed his law of gravity in the late 1600s that people knew gravity applies to everything in the universe that has mass.

Multiple Choice

Gravity affects most objects that have mass.

• True

• False

The Law of Gravity (SC.6.P.13.2)

The Universal Law of Gravitation (Newton’s law of gravity): 1. Every mass attracts every other mass.

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2. Attraction is directly proportional to the product of their masses.

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3. Attraction is inversely proportional to the square of the distance between their centers.

Multiple Choice

The Universal Law of Gravity is also know as:

• Einstein's Law of Relativity

• Newton's Law of Conservation of Mass

• Newton's Law of Conservation of energy

• Newton's Law of Gravitational Force

Newton’s law also states that the strength of gravity between any two objects depends on two factors: the masses of the objects and the distance between them.

Factors That Influence the Strength of Gravity

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​Objects with greater mass have a stronger force of gravity between them. For example, because Earth is so massive, it attracts you and your desk more strongly that you and your desk attract each other. That’s why you and the desk remain in place on the floor rather than moving toward one another.

Multiple Choice

What force enables (allows) the moon to revolve around the Earth?

• gravity

• magnetism

• the overall speed (inertia) of the moon is the primary force

• distance

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Factors That Influence the Strength of Gravity

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Objects that are closer together have a stronger force of gravity between them.

For example, the moon is closer to Earth than it is to the more massive sun, so the force of gravity is greater between the moon and Earth than between the moon and the sun. That’s why the moon circles around Earth rather than the sun. You can see this in the image on the left.

Multiple Choice

What factor(s) have an effect on the strength of gravity between 2 objects?

• The amount of mass and distance between the 2 objects

• The overall speed the objects are traveling and the distance between them

• The location of the objects (For example, the sun and moon have an effect on Earth since they are located in space)

• The overall speed of the objects, their mass and the total distance between them.