Universal Gravitation

the discovery of universal gravitation is associated with

Isaac Newton

Two objects with equal masses of 1 kg each are separated by a distance of 1 m. The gravitational force between the objects is:

Equal to G

Two objects are attracted to each-other by a gravitational force F. If one mass is doubled and the other is tripped without changing the distance, what is the new gravitational force between the objects in terms of F?

6F

Two objects are attracted to each-other by a gravitational force F. If the distance between the objects is doubled, what is the new gravitational force between the objects in terms of F?

1/4 F

A rocket moves away from the surface of Earth. As the distance "r" from the center of the planet increases, what happens to the force of gravity on the rocket?

The force decreases inversely proportional to 1/r^2

A spacecraft is orbiting Earth with an orbital radius r. Which of the following is true about the astronught's apparent weight?

The apparent weight is ZERO because the astronought is in a free fall.

A spacecraft starts on Earth moving to Mars. Which of the following is correct about the gravitational force on the spacecraft due to Earth's attraction? (in regards to distance)

The spacecraft is Never beyond the Earth's gravitational attraction.

A satellite is orbiting a planet with an orbital radius r. Which of the following diagrams represents the direction of the velocity and acceleration of the satellite?

* Acceleration is towards the CENTER

* Velocity is PERPENDICULAR to the satellite

Satellite A has twice the mass of satellite B. The satallites orbit a planet with the same orbital radius. The orbital velocity of Satellie A compared to B is _____

THE SAME

Theory of Relativity

Albert Einstein's ideas about the interrelationships between time and space and between energy and matter

"The faster you move through space, the slower you move through time"

Does acceleration due to gravity change or stay the same on different planets?

CHANGE

When does the gravitational force between two objects DECREASE?

When the distance between the centers of the two masses increase.

"r" represents ________ when solving for Gravitational Force

Distance in meters

What equation should you use to find the acceleration of both a small and large object?

EF= Ma (Larger Object)

EF= mA (Smaller Object)

Rearrange the equation so that A= EF/m OR a=EF/M

Explain how to find g at a height of 4RE ABOVE the SURFACE of Earth

Because the height is 4RE ABOVE Earth's surface, multiply the radius of Earth by 5 (One Earth Radius from the center to the surface and four Earth Radius ABOVE the surface.

* Radius of Earth from the center is 1RE

When a car is moving in a circular path, at a CONSTANT SPEED, the car is____________

ACCELERATING

When a thrower swings a heavy metal ball ("hammer") on a wire in a circular motion.

what force keeps the hammer moving in a circular direction before the wire is released?

The tension that is exerted by the thrower

When a thrower swings a heavy metal ball ("hammer") on a wire in a circular motion.

The name of the force is ___________

centripetal force

When a thrower swings a heavy metal ball ("hammer") on a wire in a circular motion.

The Tension force acts towards_____________

THE CENTER (Inward)

When a thrower swings a heavy metal ball ("hammer") on a wire in a circular motion.

_______________describes the hammer's tendency to move in a straight line

Intertia

The attraction between the Moon and the Earth is _______

EQUAL and opposite

Define Gravitational Force

Centripetal force that holds planets in orbit

The force that Earth exerts on the moon is ____________ to the force that the moon exerts on Earth

Equal & Opposite

What does "G" represent

The constant of Universal Gravitation

Tides are caused by _________

differences in the gravitational force of the moon at different points on Earth.

________________ causes objects to continue moving in the same direction.

Law of Intertia

Why is astronaut "Weightless" in Space?

Because everything in space is "falling" or being "pulled" toward Earth

Does Mass change or stay the same on different planets?

STAY THE SAME

An apple hangs on a tree on Earth. Which of the following statements is correct?

The forces on the apple and Earth are equal and opposite

Define the law of inertia

A body at rest will remain at rest and a body in motion will stay in motion

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

The force decreases by a factor of 4

How do you solve for the value of TWO EQUAL MASSES?

1. Plug in given values to Gravitational Force equation

2. For m and M write m*M OR M^2

3. Rearrange the equation and solve for M and m (same value)

Explain why astronaut weighs less on moon than Earth

1. FW= Mg and g is smaller on Moon than Earth and the mass of person is the same.

The mass of the moon is less than mass of Earth