Physics Flashcards
What is energy?
the ability to do work: that means make something happen.
What is work?
moving an object by applying a force to it.
What are energy and work done both measured in?
Joules (J)
When do we use work?
when we use a force to move an object.
When will work require more energy?
when we need to use a have a bigger force,
when we need to move the object further.
What is the equation for work done?
Force (N) x Distance (M)= Work Done
What are the 8 stores of energy?
Cats Take Every Meal Gratefully, Everyone Knows Now.
Chemical Thermal Elastic Magnetic Gravitational Potential Electrostatic Kinetic Nuclear
Name the stores energy can be transferred by.
electric
light
sound
mechanical (when a force acts on an object)
What is the percentage efficiency equation?
Efficiency=Useful energy= Useful power
——————– ——————-
Total energy Total power
How do you increase the efficiency?
The wasted energy transfer needs to be reduced with no change to the useful transfers
What is the equation for kinetic energy?
Ek=0.5 x m x v squared
What is the equation for GPE?
Egp = m x g x h
What is the equation for power?
Power = Energy/ time
What is the equation for weight?
Weight = Mass x gravity
What are the 3 methods of heat transfer?
Conduction
Convection
Radiation
Objects want to be in ____ so ____ energy will move until the temperature____ ____.
Equilibrium
thermal
balances out
What temperature objects does thermal energy move from?
hot objects to cold objects
What is conduction?
Heat transfer by molecular contact. Most effective in solids.
What does heat cause molecules to do?
Vibrate
What is convection?
Heat transfer through density differences. Effective in liquids and gases.
Why does hot air rise?
Flames cause air to expand, becomes less dense.
What is radiation?
Heat transfer by wave motion.
How does energy travel from our sun to Earth?
Radiation
Name a conductor.
a metal
Name an Insulator.
anything other than a metal lol.
How does conduction occur?
When particles begin to increase in energy they move more. When they collide with other particles in the material, they will pass on the energy.
What makes a metal conductive?
delocalised electrons
What is a delocalised electron?
Electrons that are free to move.
What is the Law of conservation of energy?
Energy can Not be created or destroyed, it’s just transferred between stores.
Name the stores energy can be transferred by.
electric
light
sound
mechanical (when a force acts on an object)
ignore
ignore
What is Radiation?
It is the emission of thermal energy.
Do different colours affect the thermal energy of an object?
They can change how much thermal energy an object will absorb or emit.
What is Specific Heat Capacity?
It is the energy required to increase the temperature of 1 kg of a substance by 1 degrees.
What is meant by Thermal conductivity?
it is the rate of thermal energy transfer via conduction.
