Unit 1: 2 - Using Energy Flashcards
What are the 7 forms of energy?
- Light
- Sound
- Gravitational potential
- Kinetic
- Nuclear
- Electrical
- Elastic potential
- Chemical (potential)
What is special about potential energy?
It is stored energy.
Any object above the ground (with mass) has what type of energy?
Gravitational potential.
A falling object transfers _____ energy to _____ energy.
Gravitational potential to kinetic.
What is the law of conservation of energy?
Energy cannot be created nor destroyed, therefore the total amount of energy is always the same.
What is a machine?
A device that transfers energy from one place to another or from one form to another.
What are the 2 types of energy we can obtain from a machine?
- Useful energy (energy transferred into the place we want and the form we want it);
- Wasted energy (which is not usually transferred).
What is the final form of energy that both useful and wasted energy will become eventually?
Heat, which will warm up the surroundings.
What is a big cause of energy loss in machines with moving parts?
Friction, which generates heat instead of useful energy.
Where is friction sometimes useful?
Brakes in bicycles and cars, as it converts some of the kinetic energy to slow the vehicle down.
What is the unit of energy?
Joules (J)
What do we call the energy supplied to a machine?
Input energy.
What is “formula” for the conservation of energy?
Input energy = useful energy transferred + energy wasted.
How do we work out efficiency?
Efficiency = Useful energy transferred / Total energy supplied (*100)
How can we graph the energy transfer through an appliance?
Using a sankey diagram.
