Gravity

Newton's Law of Universal Gravitation

All objects with mass experience attraction towards each other as a result of the gravitational force between them.

Third Law

For every action, there is an equal and opposite reaction.

If the Earth were moved to half its current distance from the Sun how would the force of gravity by the Sun on the Earth change?

It would become 4 times stronger.

What would happen to the Earth if the Sun's gravity somehow 'turned off' instantaneously?

It would continue to move in a line in the same direction it was moving when the gravity turned off.

What did Newton's Law of Universal Gravitation tell us about how gravity works?

The force of gravity from the Sun will ne stronger on an object with more mass.

If you were to sit on the ground, there would be a force due to gravity pulling you toward the Earth. Which of the following is true according to Newton's 3rd law?

You are pushing the Earth away from yourself with the same force.

Newton's First Law

An object at rest, or in motion in a straight line at a constant speed, will remain in that state unless acted upon by a force.

The Earth radius is about 6400 km. If you were in orbit in the Space Station 150 km above the ground, the force of gravity you feel from Earth would be:

Slightly weaker than when you are standing on Earth.

According to Newton's Second Law of Motion, if the net force acting on the object increases while the mass of the object remains constant, what happens to the acceleration?

The acceleration increases.

Second Law

The acceleration of a body due to a force will be in the same direction as the force, with a magnitude inversely proportional to its mass. Or: the magnitude of force necessary to produce a certain acceleration on a body will be directly proportional to its mass - a higher mass requires greater force. (Usually written as F=ma)