Physics - ENERGY (P1)

Energy stores & systems -

Name the 8 main energy stores

Thermal, kinetic, gravitational potential, elastic potential, chemical, magnetic, electrostatic, nuclear.

Energy stores & systems -

What is the difference between an energy store + an energy transfer?

An energy store - way energy’s held, while an energy transfer moves energy from one store to another.

Energy stores & systems -

Give an example of a system + describe an energy transfer w/in it.

A kettle boils water. Energy’s transferred electrically to the heating element, which transfers thermal energy to the water.

Kinetic & gravitational potential energy -

State the equation for kinetic energy.

Ek = ½ m v (squared)

Kinetic & gravitational potential energy -

What are the units of each variable in the kinetic energy equation?

Ek = joules (J)

m = kilograms (kg)

v = metres per second (m/s)

Kinetic & gravitational potential energy -

State the equation for gravitational potential energy.

Ep = mgh

Kinetic & gravitational potential energy -

What factors affect the gravitational potential energy of an object?

Mass, height above ground, + gravitational field strength.

Elastic potential energy -

What is the equation for elastic potential energy (for a spring w/in its limit of proportionality)?

Ee = ½ k e(squared)

Elastic potential energy -

What do the symbols in the elastic potential energy equation represent?

Ee= elastic potential energy

k= spring constant

e= extension

Energy transfers & work done -

Define ‘work done’.

Work done - when energy is transferred by a force moving an object through a distance.

Energy transfers & work done -

State the equation for work done.

W = Fd

w = work done

f = force

d = distance

Energy transfers & work done -

What is the unit of work done?

Joule (J)

Power & efficiency -

Define power.

Power - the rate at which energy is transferred / work is done.

Power & efficiency -

State the equation linking power, energy transferred, + time.

P = E/t

p = power

e = energy transferred

t = time

Power & efficiency -

State the equation linking power, work done, + time.

P = W/t

p= power

w= work done

t= time

Power & efficiency -

Define efficiency.

Efficiency - the ratio of useful output energy (for power) to total input energy (for power).

Power & efficiency -

State the formula for efficiency as a decimal + as a percentage.

Efficiency = (useful energy output/total energy input) x 100

Energy resources -

Name three renewable + three non-renewable energy resources.

Renewable - solar, wind, hydroelectric.

Non-renewable - coal, oil, natural gas.

Energy resources -

Give one advantage + one disadvantage of solar energy.

Advantage - renewable + no emissions.

Disadvantage - weather dependent + expensive setup.

Energy resources -

Why is reliability important when choosing an energy resource?

Reliable sources consistently provide energy when needed, which is crucial for stable electricity supply.