Conservation And Dissipation Of Energy Flashcards
What are the ways energy can be stored?
Chemical Kinetic Gravitational potential energy Elastic potential energy Thermal energy stores
What chemical energy?
These stores include fuels, foods, or chemicals found in batteries The energy is transferred during chemical reactions.
What is a kinetic store?
The energy an object has because it is moving.
What is a gravitational potential store?
The energy stored in an objects because of its position
What is an elastic potential store?
The energy stored in a springy object when you stretch or squash it.
What is a thermal energy store?
The energy a substance has because of its temperature.
What is a closed system?
Where no resistance acts upon the object. For example, a vacuum.
The total energy is the same before and after energy transfers to the other energy stores within the closed system.
What is the conservation of energy?
Energy cannot he created or destroyed.
When is work done on an object?
When an object is moved by a force. This force transfers energy to the object.
Therefore, the amount of energy transferred to the object is equal to the work done on it.
What is energy transferred equal to?
Energy transferred = Work done
Work done to overcome friction is mainly transferred to what energy store?
Thermal energy store by heating.
When you rub your hands together they become warm. Why?
Your muscles do the work to overcome the friction between your hands. The work you do is transferred as energy that warms your hands.
What is the force you need to lift an object at a constant velocity equal and opposite of?
The gravitational force on the object.
What happens when an object is moved upwards?
The energy in its gravitational potential energy store increases. This increase is equal to the work done on it by the lifting force to overcome the gravitational force on the object.
What does the work done on an object moving up or down depend on?
How far it is moved vertically - it’s change in height.
It’s weight.
What is the weight of an object in Newton’s equal to?
Mass x Gravitational Potential Field Strength.
What is useful energy?
Energy transferred to where it is wanted in the way that is wanted.
What is wasted energy?
The energy that is not usefully transferred.
Does friction cause energy to be wasted?
Yes.
What happens to the energy when you are exercising.
When you exercise, energy is transferred to the thermal energy store of your muscles (so you get hot) and to the thermal energy store of the machine by the force you exert to overcome the friction in the machine.
What energy is wasted from an electric heater?
Light emitted from the glowing element.
How do clockwork radios work?
You turn a handle which winds up a spring. When the spring unwinds, energy from its elastic potential energy store is transferred to its kinetic energy store and it turns a small electric generator in the radio. Therefore, it doesn’t need batteries or mains electricity.
What is power?
The rate of energy transfer.
What happens when energy spreads out?
Energy becomes less useful the more it spreads out. Useful energy will eventually spread out.
