physics year 9

What are the two main types of energy?

Kinetic energy (energy of moving objects) and potential energy (stored energy that can be used later).

What are examples of potential energy?

Gravitational (height), elastic (stretched rubber band, spring), chemical (food, batteries, fuel).

Define energy transformations.

Energy transformations refer to the changes from one form of energy to another, such as chemical to electrical in batteries.

What is a wave?

A wave is an energy transfer without permanently moving matter.

What are the two types of waves?

Transverse waves (vibrate up and down) and longitudinal waves (vibrate back and forth).

What are the parts of a wave?

Crest (top of wave), trough (bottom of wave), wavelength (distance between two crests), amplitude (height from middle).

What does frequency measure?

Frequency, measured in Hertz (Hz), is the number of waves per second.

How do frequency and period relate to each other?

Period is the time for one wave, and the formulas are Frequency = 1 ÷ Period and Period = 1 ÷ Frequency.

What is the wave speed formula?

The wave speed formula is v = fλ, where v is wave speed, f is frequency, and λ is wavelength.

What are the properties of sound and light waves?

Sound waves are longitudinal and light waves are transverse. Higher frequency leads to higher pitch in sound.

What is the principle of energy conservation?

Energy is never created or destroyed; it only changes form.

How do you calculate efficiency?

Efficiency = (useful energy / total energy) × 100.

What are examples of renewable and non-renewable energy?

Renewable: solar, wind, hydroelectric; Non-renewable: coal, oil, gas.

What are the three methods of heat transfer?

Conduction (through solids), convection (in liquids/gases), and radiation (heat from the Sun).

How do frequency and amplitude affect waves?

Increasing frequency decreases wavelength, and increasing amplitude increases energy (louder or brighter).