Work, Energy and Power Flashcards
What is Work done?
It is the product of the magnitude of displacement and the component of the force parallel to the displacement.
When force and displacement are in the same direction…
…workdone is constant
When the direction of force is in the opposite direction of displacement…
…workdone is negative
KE decreases
Object slows down
When the direction of force is perpendicular to the direction of displacement…
…workdone is zero,
KE is zero
There is no speed
What is the value of 1 Horsepower?
746 Watts
What is Energy?
It is the capacity to do work.
What is Mechanical Energy?
It is the energy acquired by a body when work is done on it. It could be PE or KE.
As a body goes up…
PE increases and KE decreases
For a body travelling vertically, at maximum height…
KE = 0 and the body has only PE
Just before the body hits the ground…
PE = 0 and KE = maximum
State the Work-Energy law`
For an object which moves under the influence of a given force, from one point to another, the work done by the force on the object is the change in the KE of the body.
What is the unit of Power?
J/s, Watts
Workdone
F x S or FScos@
Power
Workdone / Time
