Law of Conservation of Energy
What is the definition of the law of conservation of energy
energy can neither be created nor destroyed by transferred from one form to another
What is potential energy
stored energy
what is kinetic energy?
moving or motion
what is the formula for efficiency?
useful energy/input energy x 100
what are the two categories of energy
kinetic and potential
Heat
People also use the __________ potential energy in petrol to power cars and buses.
What is chemical?
a person running is using _________ energy?
kinetic
A machine is 90% efficient. What happens to the remaining 10% of the energy that is not converted into useful work?
What is 10% of the energy is transformed into other forms such as heat .
what type of heat transfer happens in solids?
conduction
What is the type of energy that is stored in food and is the energy of molecular bonds
chemical
a compressed spring has what type of energy?
elastic potential energy
a ball gets pushed off a table. what type of energy does it have?
kinetic
if a 400W light bulb is 50% efficient, what does that mean?
that means that 200W is being used for light and 200W is lost to heat
as a liquid is heated, what do the particles do?
move faster and expand (move further apart)
What is energy measured in?
Joules (or Kilojoules)
A ball sits on a table. What type of energy does it have?
gravitational potential energy
True False
kinetic energy can be converted to gravitational potential, heat, light and sound.
true
electrical
why is the term "don't let the cold air in" incorrect?
hot will travel from hot to cold so the hot air will travel to the outside
How many Joules are in a Kilojoule
1000J = 1KJ
Your pencil and a Science workbook are both on the table. Which has more potential energy? Explain.
What is a Science workbook because it has more mass. GPE=mgh
the bigger the object's mass the greater the __________ energy
kinetic
what would be the output of a stretched rubber band?
elastic potential
what colour absorbs heat best?
dark colours