A.3 Work, Energy and Power Flashcards
Mechanical energy
Energy possessed by an object due to it’s motion (kinetic) or position (potential)
Energy
Capacity to do work
In the absence of frictional or resistive forces, the total mechanical energy…
Is conserved
Work
When a force (F) moves an object through a displacement (s). (a transfer of energy)
What is the energy that an object loses or gains equal to?
The work done
If the force being used is not constant, the work done can be calculated by…
The average force value or the area below a force displacement graph
Centripetal force acts at 90* to…
The motion of the object undergoing circular motion
Does the centripetal force do any work in circular motion
No (no displacement in direction of the force)
Sankey diagram
Shows the flow of energy through a system and identify where the energy is lost to surrondings
Degraded energy
Energy that is lost from the system and cannot perform useful work
Power
The rate at which work is done or energy is transferred (W/Js-1)
Work formula
=force x displacement
When should you use W=Fscos0
If diplacement of the object is not along the line of action of the force
P=Fv
F is frictional force
Energy density
Energy liberated per unit volume of fuel consumed (Jm-3)
