Year 9 physics recap

physics

What is energy?

Energy is the ability to do work or cause change.

What is work?

Work is the ability to apply a force onto an object over a distance.

What is motion?

Motion is the change in position of an object over time.

What are the types of potential energy?

Gravitational, elastic, chemical, nuclear.

What is gravitational potential energy?

The energy stored in an object's position or height.

What is elastic potential energy?

The energy stored in the stretch of an object.

What is chemical potential energy?

The energy stored in the bonds of atoms and molecules.

What is nuclear potential energy?

The energy stored in the nucleus, released when the nucleus is split or combined.

What is kinetic energy?

Kinetic energy is the energy of an object in motion.

What are the types of kinetic energy?

Sound, mechanical, thermal, electrical, light.

What is sound energy?

Sound energy is the vibrations of waves through material.

What is mechanical energy?

Mechanical energy is the energy created by an object's movement.

What is thermal energy?

Thermal energy is the vibration and movement of molecules.

What is electrical energy?

Electrical energy is the movement of electrons.

What is light energy?

Light energy is electromagnetic waves.

What is current electricity?

The movement of electrons/charge with an electrical current.

What is static electricity?

The build up of a charge in one place, e.g., rubbing a balloon on your hair.

What is the difference between current and static electricity?

In current electricity, electrons continue moving inside a conductor, while in static electricity, electrons build up in one place on the surface of an insulator.

How do electrons move in a circuit?

In a circuit, electrons flow from negative to positive along wires.

What is current?

Current is the flow of electrons at a certain point in one second, measured in amperes.

How is voltage measured?

Voltage is measured in volts with a voltmeter, which is connected in parallel to the circuit.

What is resistance?

Resistance is the control of voltage in a circuit.

What are series circuits?

Circuits where the electrons can only go along one path; if one component breaks, the whole circuit breaks.

What are parallel circuits?

Circuits that have multiple paths for electrons to go through; if one component breaks, the others keep working.

What is Ohm's Law?

Ohm's Law states that V=I x R, I=V/R, and R=V/I.

How is total resistance calculated in a series circuit?

Total resistance in a series circuit is calculated as a + b = total resistance.

How is total resistance calculated in a parallel circuit?

Total resistance in a parallel circuit is calculated as 1/total = 1/a + 1/b (then flip the sum).

What is conventional current?

Conventional current is the movement of charge from positive to negative, opposite to electron movement.

What is direct current?

Direct current is when electrons flow from an energy source to the user.

What is alternating current?

Alternating current is when electrons shuffle back and forth across a wire, making it easier to control and safer.