Efficiency
What is "waste" energy?
Output energy that isn't useful.
What is the formula for calculating kinetic energy?
Ek=0.5mv2
What is the formula for Graviational PE?
EP=mgh
What is the law of conservation of energy?
Energy cannot be created or destroyed, only changed from one form to another or transferred.
A 45 N book sits on a desk. How much work occured?
0 J
What is the input, output and waste energy of a hairdryer?
Input = Electrical, Output = Heat, and Waste = Sound
What is the definition of kinetic energy?
Energy of movement
What are the four types of potential energy?
Elastic, Gravitational, Chemical and Nuclear.
What is energy transformation?
One form of energy being converted into another.
What type of energy is in batteries?
Chemical (Potential) Energy.
60 joules of electricity is input into a globe, only 6 joules of light energy is produced.What is the input and output?
60 Joules = Input, and 6 Joules = Output
A 0.5 kg ball is travelling at 4 m/s. Its kinetic energy is:
4 J
Lucy need to lift 5 kg packing boxes by 1 m into a truck. Calculate the gravitational potential energy.
49 J
What is energy transfer?
The same form of energy is passed from one object to another.
What waste energy does a light bulb have?
Heat Energy
A blender uses 300 J of electrical energy and produces 210 J of useful kinetic energy in 5 seconds. What is it's efficiency?
70 %
What are the four types of kinetic energy?
A 2kg cat jumps from 1m high table onto a shelf 2m above the table, what is its GPE?
58.8 J
What is the energy transformation in a television?
Electrical -- > Light + Sound + Heat
What units is energy measured in?
Joules (J)
A motor does 1500 J of useful work and wastes 500 J as heat.
What is the total input energy?
2000 J
A soccer ball with a mass of 0.4 kg is kicked with a velocity of 10 m/s. Calculate its kinetic energy.
KE = 0.5 x 0.4 x 102
KE = 20 J
A 2.5 kg box is lifted onto a shelf that is 1.8 m high.
Calculate the gravitational potential energy gained by the box.
44.1 J
A student uses a toaster to make breakfast.
Electrical energy → Thermal (heat) energy
The energy transformations performed in a hydroelectric dam.
Gravitational Potential --> Kinetic --> Electrical