Energy
What type of energy does a moving object have?
Kinetic
In a toaster, electrical energy is transferred into what useful form of energy?
Thermal/heat energy
What does GPE stand for?
Bonus Q: What is the formula?
Gravitational Potential Energy
What are the three methods of heat transfer?
Conduction, convection and radiation
What are the 3 components of energy efficiency?
Useful, total and wasted
What type of energy is stored in an object because of its height?
Gravitational Potential Energy (GPE)
A speaker uses electrical energy and produces sound. What is the energy transformation?
BONUS Q: What is the wasted energy?
Electrical --> Sound
W: Heat
Name the three things that affect an objects GPE
Heat travelling through a solid, such as a metal spoon, is called what?
Conduction
If a machine receives 100 J and produces 70 J of useful energy, how much energy is wasted?
30J
What type of energy is stored in a stretched rubber band?
Elastic Potential Energy
What is the difference between energy transfer and energy transformation?
An energy transfer is when energy moves from one object or place to another, while an energy transformation is when energy changes from one type to another.
Which has more GPE: a 5 kg object on the ground or a 5 kg object on a 10 m high platform?
10m platform
How does heat from the sun reach the Earth?
Radiation
What is the maximum possible efficiency of a device?
100%
What type of energy is stored in food and fuels?
Chemical potential energy
What energy transfer occurs when you kick a soccer ball?
BONUS points if you can also name the transformation?
Kinetic --> Kinetic
Chemical --> Kinetic
Calculate the GPE of a 2 kg object held 5 m above the ground.
100J
Which method of heat transfer involves the movement of particles in a liquid or gas?
Convection
Total (left), useful (right), wasted (down)
A roller coaster is sitting at the top of a hill. What type of energy does it have, and what happens to this energy as it rolls down?
Gravitational potential energy is converted into kinetic energy.
A battery powers a torch. Name the main energy transformation that occurs.
BONUS points for naming 3
Chemical --> Electrical --> Light
A 10 kg object has 500 J of GPE, how high is it?
5m
height = GPE ÷ (mass × gravity)
height = 500 ÷ (10 × 10)
You are sitting next to a campfire. You feel heat on your face even though you aren't touching the fire. What type of heat transfer is mainly responsible?
Radiation
A device takes in 200 J and produces 150 J of useful energy. What is its efficiency?
75%