Energy Flashcards
(27 cards)
What is Kinetic energy
Kinetic energy is the energy stored in MOVING objects
How do you calculate kinetic energy?
kinetic energy = 0.5 X mass X speed^2
What happens when we stretch a spring and what is this force called?
When we stretch a spring we’re applying a force to change the length of the spring, this is called doing “WORK”
What happens when we put energy into a spring to stretch it?
The stretched spring stores this energy and this energy is called Elastic Potential Energy
What is the relationship between extension and force applied?
They are directly proportional
What happens to the relationship between extension and force if a greater force is applied?
Extension is no longer directly proportional to the force, this means the spring has stretched beyond the limit of proportionality
What does it mean if a spring has stretched beyond the limit of proportionality?
It will not return back to its original shape
What is gravitational potential energy?
Gravitational potential energy is the energy an object possesses due to its position in a gravitational field.
How do you work out Gravitational potential energy?
Gpe = mass X gravitational field strength(n/kg) X height
What is Specific Heat Capacity?
It is the amount of energy required to raise the temperature of 1 Kg of the substance by 1C*
What is the energy stored due to an object’s temperature called?
Thermal energy
What is the law of conservation of energy?
Energy can be transferred usefully, stored or dissipated but it can’t be created or destroyed
What is a system?
an objects or a group of objects
In what type of system can no energy enter of leave?
A closed system
Describe the stages of energy transfer in a pendulum
At the top the mass has the maximum store of GPE, as the pendulum swings the GPE is transferred to KE, at the bottom the maximum KE of the mass is reached because it swings the fastest, as the mass swings back up the KE is transferred to GPE, the maximum GPE of the mass is reached at the top
In a pendulum where does friction occur? how can we reduce this friction?
at the fixed point and as the pendulum passes through the air particles.
By using a lubricant on the fixed point or removing the air particles from around the pendulum
Why is energy often considered ‘wasted’ in system changes?
During system changes, energy is dissipated and stored in less useful ways, leading to its classification as ‘wasted.’
What is the relationship between the thermal conductivity of a material and the rate of the heat transfer
they are directly proportional
what is work done?
it is whenever energy is transferred from one store to another
what are the two different types of work done? + explain
Mechanical work: involves using a force to move an object
Electrical work: involves a current transferring energy
How do you find the work done?
Work done (j) = Force X Distance
What is power
It is the rate at which energy is transferred / work is done
How can i calculate power?
Power (w) = Energy transferred (j) / time (s)
OR
Power (w) = Work done (J) / time (s)
What is the energy transfer of 1 watt per second?
1 Joule
