Work & Energy

Work

The amount of change in energy of a chosen system (delta(E))

• W = F * d

• Symbol: W

• Units: J or Nm

Energy

The ability of a system to do something

• Symbol: E

• Units: J

Actual Mechanical Advantage

The output that a machine produces which is bigger than the one you apply

• How easy it is to lift something

• The actual performance a machine achieves 

• (Output Force / Input Force)

Ideal Mechanical Advantage

The maximum performance a machine can achieve under ideal conditions

• How much more distance you need to exert force on a ysstem to move it where you want to 

• (Input distance / output distance)

Efficiency of a Machine Learning

(Work output / work input) * 100

• If machine is ideal, Wi = Wo

Kinetic Energy

The type of energy associated with motion

• KE = ½ mv²

• Units: J

Gravitational Potential Energy

The type of energy associated with height

• U_g = mgh 

• Units: J

Elastic Potential Energy

The type of energy associated with a compressing/stretching (springs)

• U_k = ½Kx²

• K = The slope of the F / x graph, spring constant

• Units: J

Template Equation

KE_i + U_gi + w = KE_f + U_gf

• replace U_g with U_k if spring problem