Forces
A force is described by ______ and ______.
What are strength and the direction in which it acts?
Newton's First Law of Motion states _____ .
Objects at rest will stay at rest unless they are acted on by nonzero net forces.
These types of charges attract each other.
What are the opposite charges ( - and + )?
These attract iron and materials that contain iron.
What are magnets?
The relationship between electricity and magnetism.
What is electromagnetism?
The force that pulls objects towards each other.
What is gravity?
Resistance to the change in motion.
What is inertia?
When electric charges are made to flow through a material.
What is an electric current?
Earth has a _________ around it which protects it from solar radiation.
What is a magnetic field?
List the two factors that affect the strength of an electromagnet.
What are the number of loops and the strength of the current?
The force that two surfaces exert on each other as they rub against each other.
What is friction?
Newton's Second Law of Motion states that an object's acceleration depends on _____ and ____ acting on it.
What are mass and force?
The buildup of charges on an object.
What is static electricity?
Two south poles brought near each other will _____ each other.
What is repel?
The two types of current.
What are direct current (DC) and alternating current (AC)?
Calculate the net force:
10N to the left + 8N to the right = _____
2N to the left
Calculate the momentum of a ball weighing 10kg moving at 5m/s.
Momentum = Mass x Velocity
Momentum = 10kg x 5m/s = 50kg m/s
Rubber is an excellent example of this type of material that does not allow charges to flow.
What are insulators?
These two areas have the strongest magnetic force due to the large number of magnetic field lines.
This device uses a fan to turn the armature of a motor thus making electricity.
What is a generator?
Calculate the net force:
3N to the right + 4N up = ____
5N to the upper right
Newton's third law states for every action ______ ...
...there is an equal but opposite reaction.
How difficult it is for charges to flow through an object.
What is resistance?
This part of the Earth creates the magnetism of the planet by the slow rotation of molten iron over solid iron.
What is the Earth's Core?
Explain how an electric motor works.
An electric current creates an electromagnet on a bent iron core called an armature. This causes a magnetic field around the armature. The armature is placed in a circle of magnets and is repulsed by the south side of the magnets and attracted to the north side. This causes the armature to turn.