Unit 4: Gravitational, Electric, and Magnetic Fields Flashcards
(22 cards)
What is the universal law of gravitation?
There is a gravitational attraction between any two objects depending on their masses and the distance between them.
What is the inverse square law?
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
What is a field?
An area of influence.
What is a gravitational field?
A collection of vectors, one at each point in space, that determines the magnitude and direction of the gravitational force.
What is gravitational field strength?
(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.
Why do astronauts float on the space station?
- 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.
What are satellites?
- 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.
What are the two types of satellites? (give examples)
- Natural Satellites- The moons, Earth
- Artificial Satellites- ISS, starlink network, GPS Satellites
What is a Coulomb?
The basic unit of charge.
What is the charge of an electron and a proton?
- 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
What does the law of electric charges state?
Like charges repel, opposite charges attract.
What is the electric force?
The attractive or repulsive interaction between any two charged objects.
What determines the force between two charged objects?
The force between two charged objects is directly proportional to their charges and inversely proportional to their distance.
For gravitational force name:
1. The direction of force
2. Range
3. Relative Strength
- attractive
- infinite
- 1
For electrical force name:
1. The direction of force
2. Range
3. Relative Strength
- attractive or repulsive
- infinite
- 10^37
What is Fg?
- force of gravitational attraction
- gravitational force
- measured in newtons
- don’t need to put direction because gravity is always pulling down
- attractive
What is g?
- gravitational field strength
- acceleration due to gravity
- measured in N/Kg or m/s^2
What is Fe?
- the electric force
- measured in newtons
- must include direction unless it asks for magnitude
What is E?
- the electric field
- measured in N/C
- always put direction, if no context is given in the question then the direction is parallel to Fe
What causes Earth’s magnetic field?
Earth’s solid iron core is surrounded by a fluid ocean of hot, liquid metal. The flow of liquid iron in Earth’s core creates moving electric charges (called currents), which in turn create the magnetic field.
What is the principe of electromagnetism?
Electric currents create a magnetic field.
What is the first right hand rule?
- A current carrying wire in a straight conductor will have a very regular magnetic field
- Place your thumb the direction of the current
- wrap your fingers the direction of the magnetic field.
- If the wire is placed in a circular loop the right hand rule still works and the field is stronger on the inside of the loop due to reinforcing.
