Edexcel Physics – P2
The size of the turning effect is called a turning moment. As Newton’s first law of motion states, an object will remain at rest if the forces are balanced. When the sum of the forces add to zero, a body will remain at rest or move at a constant velocity.
Forces can cause an object to rotate and the turning effect of the force is called a moment. If a resultant force acts on an object about a fixed turning point called the pivot or fulcrum it will cause the object to rotate e.g. using a spanner, a screwdriver, opening a door hanging on hinges.
When a force acts on a spring it is stretched or compressed, its length will changes by an amount e from its original length.
Pressure can be calculated if you know the force applied to or by an object and the contact area. The units are newtons per square meter, or N/m2.
In physics, the kinetic energy (KE) of an object is the energy that it has due to its motion. It is defined as the work needed for an object of a known mass to accelerate to a given velocity.
Specific heat capacity is how much heat energy is required to raise 1 kg of a substance by 1 °C.
The quantity power is the rate at which work is done. The quicker work is done the greater the power.
Stretching or squashing an object can transfer energy into its elastic potential energy store.
The size of the current is the rate of flow of charge. Electrons are negatively charged particles which transfer energy through wires as electricity.
Resistance is an electrical quantity that measures how a device or material reduces the electrical current flow through it.
Resistors in series and in parallel can change the total resistance in a circuit.
The power of an appliance is the energy that is transferred per second. Electric power is the rate, per unit time at which electrical energy is transferred by an electric circuit.
Density is a measure of how compact the particles are in a substance. Density is defined as the mass per unit volume.
Specific latent heat is the energy needed to change the state of a substance.
Lifting an object in a gravitational field transfers energy into the objects gravitational energy store. Gravitational potential energy is the energy an object has due to its height above Earth.
The efficiency of a device is the proportion of input energy that is converted to useful energy.
The potential difference between two points is the energy transferred per unit charge. An electrical circuit is an energy transformation device.
The unit for work done is the joule (J), or Newton meter (N-m). One joule is equal to the amount of work that is done when 1 N of force moves an object over a distance of 1 m.
A transformer is an piece of electrical apparatus which will increase or decrease the voltage in an alternating current. It can be designed to “step up” or “step down” voltages and is based on the magnetic induction principle.
A current-carrying wire or coil can exert a force on a permanent magnet. The force increases if the strength of the magnetic field and/or current increases. This is called the motor effect.
Gas Pressure is created when gas particles collide with the walls of their container. The more often the particles collide with the walls, and the faster they are moving, the greater the pressure.
Fluid pressure is exerted on the surface of an object in a liquid. This pressure causes upthrust . An object placed in a liquid will begin to sink. As it sinks, the liquid pressure on it increases and so the upthrust increases.
