AQA GCSE Physics Topic 1: Energy

Flashcards for AQA GCSE Physics Topic 1: Energy

What is a system?

An object or group of objects.

What happens when a ball rolling hits a wall in terms of energy?

Kinetic energy is transferred as sound.

When a vehicle slows down, what energy transfer happens?

Kinetic energy transfers to thermal energy due to friction between wheels and brakes.

What is the formula for Kinetic Energy?

𝐸𝑘 = 1/2 * mv^2

What does 'm' stand for in the kinetic energy formula?

Mass in kilograms (kg).

What does 'v' stand for in the kinetic energy formula?

Speed in metres per second (m/s).

What does 'Ek' stand for in the kinetic energy formula?

Kinetic energy in joules (J).

What is the formula for Elastic Potential Energy?

𝐸𝑒 = 1/2 * ke^2

What does 'Ee' stand for in the elastic potential energy formula?

Elastic potential energy in joules (J).

What does 'k' stand for in the elastic potential energy formula?

Spring constant in newtons per metre (N/m).

What does 'e' stand for in the elastic potential energy formula?

Extension in metres (m).

What is the formula for Gravitational Potential Energy?

𝐸𝑝 = mgh

What does 'Ep' stand for in the gravitational potential energy formula?

Gravitational potential energy in joules (J).

What does 'g' stand for in the gravitational potential energy formula?

Gravitational field strength (9.8 N/kg).

What does 'h' stand for in the gravitational potential energy formula?

Height in metres (m).

What is Specific Heat Capacity?

The energy required to raise the temperature of 1kg of a substance by 1°C or 1K.

What is the formula for the relationship between energy, mass, specific heat capacity, and temperature change?

𝐸 = mcΔT

What does 'ΔE' stand for in the specific heat capacity formula?

Change in thermal energy in joules (J).

What does 'm' stand for in the specific heat capacity formula?

Mass in kilograms (kg).

What does 'c' stand for in the specific heat capacity formula?

Specific heat capacity in joules per kilogram per degree Celsius (Jkg−1°C−1).

What does 'ΔT' stand for in the specific heat capacity formula?

Temperature change in degrees Celsius (°C).

What is Power defined as?

The rate at which energy is transferred or the rate at which work is done.

What is the formula for Power?

𝑃 = 𝐸/t = 𝑊/t

What does 'P' stand for in the Power formula?

Power in watts (W).

What does 'E' stand for in the Power formula?

Energy transferred in joules (J).

What does 't' stand for in the Power formula?

Time in seconds (s).

What does 'W' stand for in the Power formula?

Work done in joules (J).

What is equal to a power of 1 watt?

An energy transfer of 1 joule per second.

What happens to energy?

Energy can be transferred usefully, stored, or dissipated but cannot be created or destroyed.

What causes energy to be dissipated into less useful ways?

Friction (leading to heat).

Give an example of lubrication?

Oil in a motor.

How does lubrication reduce energy waste?

Reduces friction, so less energy is lost as heat.

Give an example of thermal insulation?

Double Glazing.

How does thermal insulation reduce energy waste?

Less useful thermal energy lost.

What is Thermal Conductivity?

The higher the thermal conductivity of a material, the more easily heat travels through it.

How can you reduce thermal conductivity in a building?

Rate of cooling is low if walls are thick and thermal conductivity of the walls are low.

What is the ratio formula for efficiency?

useful energy output / total energy input = useful power output / total power input

What are the two ways that the efficiency of a system can be increased?

Reducing waste output and recycling waste output.

What are non-renewable energy sources?

Fossil fuels (coal, oil, gas) and Nuclear Fuel.

What are renewable energy resources?

Biofuel, Wind, Hydro-electricity, Geothermal, Tidal, Solar, Water waves.

What is renewable energy?

Energy that can be replenished as it is used.

Why is non-renewable energy used more for large-scale energy supplies?

Large energy output per kilogram of fuel.

Why is renewable energy not always reliable?

Solar doesn’t work in bad weather or night and wind is only intermittent.

What are the main energy uses?

Transport, electricity generation, heating.

What are some environmental impacts of energy extraction?

Fossil fuels involve destroying landscapes and wind turbines can be considered an eyesore.

What are some environmental impacts of using energy sources?

Fossil fuels release harmful emissions and solar, wind directly create electricity with no emissions.

Why did fossil fuels become an important source of energy during the industrial revolution?

Fossil fuels became an important source of energy as it was easy to mine, and provided a lot of energy.

Why has renewable energy only recently become more suitable?

Technology has had to develop a lot since the industrial revolution to be able to harness such energy sources efficiently.

What makes it easier to use energy resources?

Increasing pressure to cope with the public’s increasing power demands.

What makes it harder to solve environmental issues?

Political, social, ethical and economic considerations.