Phisics QQQ

What are three stores of energy?

Chemical, Kinetic, Gravitational Potential, Elastic Potential, Thermal Energy, Magnetic, Electrostatic

Name 2 types of energy that is wasted in a car.

Thermal, chemical

Describe the energy transfer when bungee jumping.

Kinetic to elastic potential to kinetic

What is energy measured in, in terms of unit?

Joules (J)

What does conservation of energy mean?

Energy cannot be created or destroyed, only transferred.

At what point on a pendulum is the maximum kinetic energy present?

At the lowest point (pendulum is straight).

What is a closed system?

Energy cannot enter or leave the system.

What is the formula for work done?

Work done = force x distance.

What force does a brake pad use in order to slow down the car?

Friction between pad and tyre.

What contact force causes an object to slow down?

Friction.

When is work done?

When an object is moved by a force.

How can you calculate the change of gravitational potential energy?

Change GPE = mass x Gravitational Field Strength x change in height.

What is the definition of gravitational potential energy?

The potential energy an object depends on its mass, the planet it is on (its GFS), and its height from the ground.

Name one way to decrease the gravitational potential energy of an object.

Lower or drop it.

What is the formula used to calculate elastic potential energy?

EPE = 1/2 x spring constant x extension.

What law can a force-extension graph show?

Hooke's law.

What is the formula for kinetic energy?

KE = 1/2 x mass x velocity².

What does energy dissipation mean?

Energy that dissipates spreads out and becomes less useful.

What does the term useful energy mean?

Energy transferred to where it is wanted to do the job that is intended.

What does the term wasted energy mean?

Energy that is not usefully transferred.

If useful energy is 250J and total energy is 2000J, what is the efficiency?

Efficiency = (250/2000) x 100 = 12.5%.

Name two examples of how you could improve efficiency.

Increase useful energy output, Decrease total energy output.

What does the term efficiency limit mean?

This is the maximum amount of energy transferred to useful energy within a closed system.

What is the formula used to calculate efficiency?

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

What is the useful energy in a kettle?

Thermal energy.

What is the wasted energy in a car engine?

Thermal energy, energy transferred as sound waves.

What is the useful energy in a TV?

Energy transferred as sound and light waves.

What is power measured in, in terms of units?

Watts (W).

What is power?

The amount of energy supplied per second.

What is the equation to calculate power?

Power (in watts) = Energy transferred to appliance (in joules) / time taken for energy to be transferred (in seconds).