Physics

Front 1

Speed

Back 1

Average speed is calculated in m/s using TOTAL DISTANCE/TIME

Front 2

Velocity

Back 2

•Velocity is an objects speed in a give direction
•A change in velocity is called acceleration
•Change in velocity= Change - Original Velocity

Front 3

Acceleration

Back 3

acceleration= change in velocity/time taken

Acceleration= force (n) / mass (g)

A negative acceleration (deceleration) means that the object slows down

Front 4

Resultant Force

Back 4

•The single force that would make an object move in exactly the same way as all the original forces acting together
• If there is no resultant force, forces are balanced. It remains stationary.
• If there is a resultant force, the object accelerates in the direction of the unbalanced force

Front 5

Energy transfer and Waste

Back 5

• The Law of Conservation of Energy States that energy cannot be created or destroyed when it is transferred. All energy is usefully transferred, dissipated, or stored

• Energy=Power x Time

Front 6

Efficiency

Back 6

Efficiency = Useful Energy / Total energy in

The answer is always a decimal less than 1

Front 7

Refraction

Back 7

•Waves can be refracted (change direction)
• They change speed in different materials.

Front 8

Reflection

Back 8

•Waves can be reflected
• The angle reflected is the same as the angle between an incoming Ray and the normal

Front 9

Diffraction

Back 9

• Waves can be diffracted (Spread out through a gap or round an obstacle)
• Diffraction is greatest when the wavelength is about the same size as the gap or obstacle.

Front 10

Electromagnetic Spectrum

Back 10

• Electromagnetic radiation is a continuous spectrum of transverse waves carrying energy
• Velocity can be calculated with;
Speed=frequency x wavelength
• The shorter the wavelength of an electromagnetic wave, the higher the frequency
• Electromagnetic waves with a short wave length & high frequency carry most energy

Front 11

The National Grid

Back 11

• Power (watts) = Voltage (v) x Current (amp)
• Step up transformers- increase the voltage to 400,000V
• Increasing voltage in power cables reduces the current. Wires heat up less, so thinner cables are needed and less energy is wasted
• Step down transformers in substations reduce reduce the voltage. Electricity is supplied at 230 V in homes

Front 12

Sound

Back 12

• Vibrating objects creates sound waves are longitudes mechanical waves and cannot pass through a vacuum
• All sounds can reflected, refracted or diffracted
• Loud sound waves have a large amplitudes; quiet sound waves have a small amplitude
• High pitched notes have a short wavelength and high frequency; low pitched sounds have a long wavelength and low frequency. High frequencies carry more energy

Front 13

Ohms Law

Back 13

• For some materials, voltage is proportional to current, and resistance is constant
• A voltage-current graph can be used to find the current in wire at a certain voltage. These values are used to calculate resistance.

Front 14

Resistance

Back 14

• Resistance is calculated using;
Resistance= voltage / current