
Equation of Work
W=F„d = (Fcosθ)d


Work is positive if
the force, or a component of force, acts in the same direction as the displacement

Work is negative if
a force, or a component of force, acts in the opposite direction of displacement

No work if
force is perpendicular to displacement, or if there is no displacement




Formula or stretching or compressing a string
W=½kx^{2}

Formula for Kinetic Energy
K=½mv^{2}

Formula for Potiental Energy: Spring
U_{s}=½kx^{2}

Formula for Potiental Energy: Gravitational
U_{g}=mgy

Formula of Conserved Energy

What conserves energy?
Spring and Gravity

What does not conserve energy? (Nonconservative)
Friction

Formula of Total Energy
 E_{0}+W_{nc}=E
 K_{0}+U_{0}+W_{nc}=K+U

Steps for solving energy problems
 1) Draw Diagram
 2) Indicate Initial and Final Position
 3) Indicate where gravitational poteintal energy is zero
 4) Use E_{0}+W_{nc}=E

Formula of Power
P=Work/Time

Units of Power
 (W) Watt
 1 J/S = 1 W
 I hp = 746 W


Formula of Efficiency
E = W_{out}/E_{in}

Formula for Linear Momentum
P=mv

