Unit 4: Gravitational, Electric, and Magnetic Fields

Question 1

What is the universal law of gravitation?

Answer 1

There is a gravitational attraction between any two objects depending on their masses and the distance between them.

Question 2

What is the inverse square law?

Answer 2

Fg is proportional to m1xm2
- As mass increases so does Fg
- if m doubles, Fg doubles
Fg is proportional to 1/ r^2
- If r doubles, Fg decreases by a factor of 4

Question 3

What is a field?

Answer 3

An area of influence.

Question 4

What is a gravitational field?

Answer 4

A collection of vectors, one at each point in space, that determines the magnitude and direction of the gravitational force.

Question 5

What is gravitational field strength?

Answer 5

(g) is the gravitational force acting on each kilogram of mass. This is the equivalent to acceleration due to gravity. g varies with distance, so Fg=mg works on Earth but fails once we leave Earths surface.

Question 6

Why do astronauts float on the space station?

Answer 6

• They are in free fall
• Gravity is causing all objects to fall at the same rate, resulting in appearance of weightlessness, or what is known as microgravity.

Question 7

What are satellites?

Answer 7

• A satellite is an object or body that revolves around another body that usually has much more mass than the satellite.
• Satellites are projectiles, meaning the only force acting upon them is gravity.
• A satellite of the Earth, such as the moon, is constantly falling. But it does not fall towards the Earth, rather it falls around the Earth.
• The motion of an orbiting satellite

Question 8

What are the two types of satellites? (give examples)

Answer 8

1. Natural Satellites- The moons, Earth
2. Artificial Satellites- ISS, starlink network, GPS Satellites

Question 9

What is a Coulomb?

Answer 9

The basic unit of charge.

Question 10

What is the charge of an electron and a proton?

Answer 10

• The charge of a single electron is -1.60 x 10^-19 C
• The charge of a single proton is +1.60 x 10^-19 C

Question 11

What does the law of electric charges state?

Answer 11

Like charges repel, opposite charges attract.

Question 12

What is the electric force?

Answer 12

The attractive or repulsive interaction between any two charged objects.

Question 13

What determines the force between two charged objects?

Answer 13

The force between two charged objects is directly proportional to their charges and inversely proportional to their distance.

Question 14

For gravitational force name:
1. The direction of force
2. Range
3. Relative Strength

Answer 14

1. attractive
2. infinite
3. 1

Question 15

For electrical force name:
1. The direction of force
2. Range
3. Relative Strength

Answer 15

1. attractive or repulsive
2. infinite
3. 10^37