Energy Flashcards
How many main stores of energy are there?
7
The energy stored when repelling poles have been pushed closer together or when attracting poles have been pulled further apart is called?
Magnetic
The energy of a moving object is called?
Kinetic
The energy stored in the nucleus of an atom is called?
Nuclear
The scientific way of saying that energy has been transferred is called?
Work
When energy is transferred, not all is directly converted as intended and some of that energy is?
Dissipated
Dissipation is a term that is often used to describe ways in which energy is wasted.
Any energy that is not transferred to useful energy stores is said to be wasted. Why?
Because energy is lost to the surroundings.
In a mechanical system, energy is dissipated when two surfaces rub together. Work is done which causes heating of the two surfaces. This work done is called?
Friction
Energy can be transferred usefully, stored or dissipated, but it cannot be?
Created or destroyed.
What type of energy does a skydiver lose when he jumps out of a plane?
Gravitaional Potential Energy
When a skydiver jumps out of a plane, he begins to lose gravitational potential energy as his height decreases. This energy is transferred to what type of energy as his speed increases as he falls?
Kinetic Energy
The amount of kinetic energy in a moving object can be calculated using the equation?
Kinetic Energy=1/2 x mass x speed2
Work is defined as?
The product of net forces on object and the distance the object is moved
When a force causes a body to move, work is being done on the object by the force. Work is the measure of energy transfer when a force (F) moves an object through a distance (d).
The equation for work is?
Work= Force (N) x Distance (meters)
The units of work are:
Joules (J)
What is the law of conservation of energy?
Energy cannot be created or destroyed.
What is the most important component when determining kinetic energy?
speed
Define Kinetic Energy?
Energy of motion
Define Potential Energy?
Energy that is stored and held in readiness
Define energy?
Ability to do work
What is the difference between potential and kinetic energy?
Potential is the amount of energy stored and kinetic is in amount of energy in motion
What does potential energy depend on?
Mass and height
What does kinetic energy depend on?
Mass and velocity
What is power?
Rate at which work is done
What is mechanical energy?
Sum of all energies
The SI unit for power is called the?
Watt
What is Chemical Energy?
The energy stored in chemical bonds
When work is done, energy has been?
Transferred
When work is done, energy has been transferred from one energy store to another, and so:
Energy transferred = Work done
Energy transferred and work done are both measured in Joules (J).
The amount of work done when a force acts on a body depends on two things:
- The size of the force acting on the object
- The distance through which the force causes the body to move in the direction of the force
What is the Work Done:
A force of 10 N causes the box to move a horizontal distance of 2 m, so:
W = F x D
W= 10 x 2
W=20J
When work is done on an object, energy is transferred. The rate at which this energy is transferred is called?
Power
The equation used to calculate power is?
Power = W/T
An electric motor is used to lift a 2 N weight through a vertical height of 10 m, in 10 seconds. What is its power?
Work Done =FxD (2 x 10)
Power = W/T
P= 20J/10s = 2W
How good a device is at transferring energy input to useful energy output is called?
Efficiency.
How is thermal energy transmitted through a conductor?
Easily
What happens to the Ions when one end of a metal rod is put into a fire?
They vibrate faster
How does an insulator affect the transfer of energy?
It tries to prevent the transfer of energy
Applying heat to one end of a metal rod, what type of energy is occuring within the rod?
Conduction
A material that heats the quickest is said to have a high thermal?
Conductivity.
When materials are heated, the molecules gain which type of energy?
Kinetic
The specific heat capacity of a material is the energy required to raise?
One kilogram (kg) of the material by one degree Celsius (°C).
Which is the best insulator?
- Copper
- Tin
- Wood
Wood
What is a thermal conductor?
A material that easily allows thermal energy through
Why is loft insulation so effective?
- It traps air which helps to reduce heat lost from the home
- It is itchy but reduces noise in the loft
- The fibres do not burn easily if there is a fire
It traps air which helps to reduce heat lost from the home
What would make the best material for wrapping around a mug to keep a hot drink warm for as long as possible?
- Aluminium foil
- Bubble wrap
- Copper foil
Bubble Wrap
What happens to the molecules in a liquid as it gets hotter?
- Speed up
- Slow down
- Stay at the same speed
Speed Up
What happens to the molecules in a solid as it gets hotter?
- Start vibrating
- Vibrate faster
- Vibrate slower
Vibrate faster
When doing an experiment to find the specific heat capacity, which of these items of equipment is not needed?
- A heater
- A force meter
- A thermometer
A force meter
If the same amount of heat energy were to be provided to a block of twice the mass of the same material, what would happen to the temperature rise?
- It would be double
- It would be the same
- It would be half
It would be half
The temperature rise would be half as much. If there is twice as much mass then the same energy must spread out twice as far so each particle does not gain as much energy as before.
