P1. Conservation & Dissipation Of Energy Flashcards
(19 cards)
What are the 8 different energy stores?
1) Thermal Energy
2) Kinetic Energy
3) Gravitational Potential Energy
4) Elastic Potential Energy
5) Chemical Energy
6) Magnetic Energy
7) Electrostatic Energy
8) Nuclear Energy
What is a system?
It is just another word for one object or a group of objects
When is energy transferred?
When a system changes
From what to what can energy be transferred?
It can be transferred into of away from the system, between different objects in the system or between different types of energy stores.
What is an example of energy being transferred by heating?
1) Boiling water in a kettle, water is the ‘system’. Energy is transferred to the water from the kettles heating element by heating, into the water’s thermal energy store(causing the temperature of the water to rise).
2) You may also think the kettle’s heating element and the water as a two-object system. Energy is transferred electrically to the thermal energy store. Of the kettle’s heating element, which transfers energy be heating to the water’s thermal energy store.
What is work done?
Energy transferred
When can work be done?
Work can be done when a current flows or by a force moving an object
Describe the transfer of energy in a person throwing a ball
The INITIAL FORCE exerted by a person to throw a ball upwards does WORK. It causes an energy transfer FROM the CHEMICAL ENERGY STORE of the person’s arm, to the KINETIC energy store of the ball and arm
Describe the transfer of energy of a ball dropped from a height
A ball DROPPED from a height is accelerated by GRAVITY. The GRAVITATIONAL FORCE does WORK. It causes energy to be transferred from the BALL’S GRAVITATIONAL POTENTIAL energy store to its KINETIC energy store.
Describe the transfer of energy in a car’s wheel
The friction between a car’s BRAKES and its WHEELS does WOEK as it SLOWS DOWN. It causes an energy transfer from the WHEEL’S KINETIC ENERGY stores to the THERMAL energy store of the SURROUNDINGS.
What does Kinetic energy mean?
Energy on a moving object
What is power?
Rate of doing WORK
What is one really IMPORTANT principle about energy (conservation of energy principle)?
Energy can be TRANSFERRED usefully, stored or dissipated but can NEVER be CREATED or DESTROYED.
What does lubrication do?
Reduces frictional force
What can heating occur by?
Conduction or Convection
What is Conduction?
When an object is heated, energy transferred to the kinetic energy stores of its particles. This causes the particles to vibrate more and to collide with each other. During these collisions, energy is transferred between the particle’s kinetic energy stores.
What is Thermal Conductivity?
Thermal conductivity is a measure of how quickly energy is transferred through a material in this way. Materials with a high thermal conductivity transfer energy between their particles at a faster rate.
What is Convection?
Because liquids and gases can flow, the warmer and less dense region will rise above denser, cooler regions. So energetic particles move away from hotter to cooler regions.
What is efficiency?
The less energy that is wasted in this energy store, the more efficient the device is said to be.
