Gravitation

The gravitational attraction between an object near the Earth's surface and the Earth.

• normal force

• weight

• friction

• tension

Formula for getting the weight, or gravitational force, of objects near the Earth's surface.

• w = m/g

• w =mg²

• w = mg/2

• w = mg

As the Earth pulls on the ball with force magnitude mg,

• The ball also pulls on the Earth with force magnitude mg

• The ball also pulls on the Earth with a much lesser force magnitude

• The ball doesn't pull on the Earth at all.

• The ball pulls with a much greater force on the Earth

Who discovered the Law of Gravitation?

• Thomas Edison

• Albert Einstein

• Isaac Newton

• Galileo Galilei

Which of the following statements is most true about Newton's law of gravitation?

• It is a force that objects with big mass apply on objects with much smaller masses.

• It is a force that exists between any two bodies with mass

• It is a force that exists between planets, stars and other heavenly bodies.

• It is a force that pushes objects around a circle in orbit.

The gravitational force

• can be attractive or repulsive

• is tangential to the orbital path

• is always repulsive

• Is always attractive

The gravitational force between the Sun and the Earth

• points away from each other

• points toward each other

• for the sun, pointing upwards; for the earth, pointing downwards

• only the sun exerts a gravitational force on the Earth

Comparing the value of the gravitational force that the Earth and sun exerts on each other,

• F on earth > F on sun

• F on sun > F on earth

• F on sun = F on earth

• F on sun is nonzero, F on earth = 0

Here the mass of the Sun is doubled, while the mass of the Earth is kept the same.

• F_g (gravitational force between Earth and mass) is halved

• F_g is doubled

• F_g is quadrupled

• F_g stays the same

Here the mass of the EARTH is doubled, while the mass of the Sun stays the same. Fg...

• is doubled for the Earth but stays the same for the Sun

• is halved

• is doubled

• stays the same