Work, Power, Energy Flashcards
Define work done
The product of the force and the distance moved in its direction
Equation for work done
w = F𝑥cosθ
F = force
𝑥 = displacement
θ = angle between the force and direction
When is work done maximum?
When θ = 0
(Force is parallel to displacement - not at an angle)
W=f𝑥
When is work done minimum?
When θ = 90°
(Force is perpendicular to displacement - not at an angle)
Work done is 0 in the horizontal direction
W=f𝑥(scos90°)
Base unit of work done
F = m a
W = F𝑥cosθ
W = m a 𝑥 cosθ
W = kg ms⁻² m …°
Work done (J) = kg m² s⁻²
Principle of conservation of energy
Energy cannot be created or destroyed it can only be transferred from one form to another
Equation for conservation of energy
▵E = W
Efinal-Einitial = Work done on a system
Equation for potential energy
Ep = mgh
m = mass
g = 9.81
h = height
Equation for kinetic energy
Ek = 1/2mv²
Definition of power
The rate of work done
Or the rate of energy transferred
Equation for power
P = W/t
P = f𝑥/t
P = f x V
How do you calculate efficiency?
Useful output energy/total input energy x 100
