Calculating the Gravitational Force

Mr. Anderson explains gravitational force in this AP Physics video. He discusses why objects in space appear weightless, using Newton's cannonball thought experiment to illustrate how satellites orbit Earth. The video introduces Newton's law of universal gravitation, explaining the equation and the gravitational constant. Mr. Anderson demonstrates how to calculate gravitational force between two masses and provides an example problem involving the moon. The video concludes by reinforcing the concept that gravity is always present, even in orbit.

Why do astronauts feel weightless in space?

• There is no gravity in space.

• They are in free fall, constantly missing Earth.

• The gravitational force is stronger in space.

• They are too far from Earth to feel gravity.

What happens to a cannonball if it is launched fast enough from a mountain?

• It will orbit around the Earth.

• It will float in space.

• It will fall back to Earth.

• It will escape Earth's gravity.

What does Newton's law of universal gravitation help us understand?

• The speed of light.

• The force between two masses.

• The energy of a moving object.

• The temperature of stars.

What is the value of the gravitational constant, G?

• 9.8 m/s²

• 1.6 x 10⁻¹⁹ C

• 6.67 x 10⁻¹¹ N(m/kg)²

• 3.14

How does the gravitational force change if the distance between two objects is doubled?

• It halves.

• It quadruples.

• It doubles.

• It reduces to a fourth.

What additional information is needed to calculate the gravitational force on the moon?

• The speed of the moon.

• The mass of the moon and the distance from its center.

• The color of the moon.

• The temperature of the moon.

What is the gravitational force between two 3.0 kg masses 2.0 meters apart?

• 9.0 x 10⁻¹⁰ N

• 1.5 x 10⁻¹⁰ N

• 3.0 x 10⁻¹⁰ N

• 6.0 x 10⁻¹⁰ N