Definitions
Energy is defined as
the ability to do work
What is kinetic energy?
moving energy
What is an energy transfer?
when energy moves from one object to another and the energy is the same type.
What is the useful energy output of a torch?
light
True of False: You can see energy
False: you can see the effects of energy but not energy its self.
Identify the kinetic energy in a bungie-jump
1. Movement (100)
2. Sound (100)
Name the 4 types of potential energy types
1. Gravitational (gravity) (50 points)
2. Nuclear (50 points)
3. Chemical (50 points)
4. Elastic (50 points)
Give an example of an energy transformation
100 points for 1 energy and 100 points for the other
Useful: Energy transformed that is useful. (100)
Wasted: Energy transformed that is useless.(100)
The dependent variable is the variable that is ....
measured in an experiment (150 point)
changes because of the independent (300 points)
Energy that moves /from light waves.
What is the definition of Potential Energy
Energy that is stored in any object or substance (150)
It has the ability to give energy (150)
What is energy measured in? Include the unit symbol.
What are the outputs for a electric heater?Answer must start with useful energy. (no J required)
light (wasted) (50 points)
sound (wasted) (50) and movement (wasted) (50)
What does work mean?
Work means doing any task including how objects change and move.
What is the technical definition of Electrical energy?
The energy you get when electrons flow from place to place.
What has more potential energy? A basket ball held at 100 cm or a tennis ball at a 100 cm?
basket ball because it has more mass
What is the definition for energy input and output?
Input energy: Energy entering the system (200)
Output energy: Energy leaving the system (200)
Is this efficient? A computer is run using electricity (2000J) to light the screen(1200J), but heat (600J) and sound (200J) are also produced.
yes: 1200 useful and 800 wasted = 60% efficient
Energy can not be created or destroyed (250)
it can only be transferred or transformed (250)
list the 5 types of kinetic energy and give an example for each one.
4. sound 5.electrical
What is the potential and kinetic energy in the Sun?
Potential:Nuclear (200 points)
kinetic: light (100) heat (100 points) sound (100)
What is a system? Give an example and describe what happens to the joules in a system if it follows the law of conservation of energy:
Energy systems show how energy transforms or transfers in any object. (200)
example: (100)
joules stay the same in input and output (200)
Energy efficiency (%) = useful energy output/energy input x 100
Calculate the following: A toaster uses 800J of electrical energy and produces 500J heat energy, 100J light energy and 200J of sound energy. is this energy efficient?
500/800= 0.62 x 100 = 62% energy efficient