Gravitational Fields
Identify the two variables that determine the strength of the force in a gravitational field
The mass of the objects and the distance between them
Identify the type of field that can both attract and repel objects
An electric field
A north pole experiences a force ________ another north pole
that repels it from
Provide the definition of a "Field" according to Field Theory
A region of space where an object experiences a force
What is the gravitational field produced by a 5.0x1023 kg planet with radius of 3.2x106 m at its surface?
How much force acts on a 70 kg person standing on the surface of this planet?
g = 3.26 m/s2
F(g) = 228.2 N
Move the particles apart
Describe the field strength in an area where electric field lines are drawn very close together
The field is stronger in that area
Draw the path magnetic field lines take between a North and South pole
They travel from the North pole to the South pole
As a comet falls toward a planet and gains a massive amount of speed (Kinetic Energy), what must be happening to the Gravitational Potential Energy of the field?
It is decreasing (it is being converted into kinetic energy)
What is the electric field produced by a 5.0x10-6 C charge at a distance of 2.5x10-9 m away?
How much force would act on a 3.0x10-6 C charge placed at this distance
E = 7.19 x 1021 N/C
F(e) = 2.16 x 1016 N
Describe what happens to an object’s weight as it moves further away from a planet's surface
It decreases because the gravitational field strength weakens with distance
How can you increase the energy stored in the electrical field between two positive charges?
Push the particles together
Describe the specific state an electric charge must be in to create a magnetic field
The charge must be moving (or in the form of a current)
If the distance between two planets is tripled (3x further), the gravitational pull between them becomes how many times weaker?
9x weaker
A positive charge moves toward the ceiling, there is a magnetic field in the room from right (N) to left (S). In what direction will the charge be pushed?
The charge will be pushed toward you (back of room)
Use the inverse square law to predict the force change if the distance between two masses is doubled
The force becomes one-fourth (1/4) of the original
Why doesn't the electric field effect things at long ranges?
Because opposite fields overlap and cancel out
Describe how to maximize the potential energy stored in a field between two positive charges
Push them closer together
If you are moving two particles and their potential energy is increasing, what can you conclude about the direction you are moving them relative to their natural force?
You are moving them in the opposite direction of their natural force (doing work against the field)
An electrical charge is moving toward the front of the room. The magnetic field in the room goes from your left (N) to right (S). What direction is the force on the charge
downwards
Explain why there is a tidal bulge on BOTH sides of the Earth rather than just the side facing the moon
Tides are formed because the Moon’s gravitational pull is stronger on the near-side water, weaker on the Earth itself, and weakest on the far-side water, creating a difference in force that stretches the ocean into two opposite bulges
Explain why a person inside a car is safe from a lightning strike, even though the same car provides zero protection against the Earth's gravitational pull
Electric fields can be shielded (blocked) by conducting materials like the metal frame of a car, whereas gravitational fields cannot be shielded and pass through all matter
Identify what would happen to the magnetic field surrounding a wire if the electrical current flowing through that wire were to come to a complete stop
The magnetic field would disappear (because magnetic fields require moving charges/current to exist)
Older scientists struggled to explain how objects could affect each other through empty vacuums. How does "Field Theory" solve this problem, specifically regarding how a massive sun can change the path of light?
Objects don't "reach out" to each other; instead, a mass (like the sun) warps or curves the field of space itself. Light simply follows the "straight" path through that now-curved space
As a comet gets further away from the Sun, it slows down. At its furthest point, what is at its maximum: Kinetic Energy or Potential Energy?
Potential Energy (Distance is maximized)