Energy Flashcards
(15 cards)
What is the definition of energy?
The capacity to do work
Give 4 examples of energy stores
Gravitational potential
Kinetic
Thermal
Elastic potential
Give three ways that energy can be transferred
Radiation
Electrically
Mechanically
What is the unit for energy?
Joules
What is the principle of conservation of energy?
Energy cannot be created or destroyed. It can only be transferred
What is the definition of work?
Force x distance moved in the line of action of the force
When a force acts at an angle, what is the equation for work done?
W = Fcos(theta) x distance
If the angle of the direction of the force is 90°, what is the value of work done?
Cos90 = 0 therefore the work done is 0
What does the area under a force - distance graph represent? If the force is constant or variable
Work done
What does the area under force - extension graph?
Work done
What is power defined as?
The rate of transfer of energy
What is the equation for power, involving force and speed?
Power = force x speed
What is negative work?
An object that causes another object to lose energy does negative work against the object. The objects have 180°
Give an example of a common force that does negative work
Friction
What does change in GPE depend on?
It depends on the change in height only
