Work Equation [Constant Force]
W = F \Delta r \cos \theta
Units in Joules
Work Equation [Non-constant Force]
W = \int_{x_i}^{x_f} F_x dx
Hooke’s Law
F_s = -k\Delta x
k is the spring constant, it is non-negative. K is in Nm.
Work done by a Spring Force
W_{F_s} = -\Delta U = \int_{x_i}^{x_f} F_s = \frac{{kx_i}²}{2} -\frac{{kx_f}²}{2}
Kinetic Energy
K = \frac{1}{2}mv²
Units in Joules
Potential Energy
U = mgh
Units in Joules
Conservation of Mechanical Energy
E_i = E_f
Applies to systems where only conservative forces act, non-conservatives forces do not conserve energy within the system.
Work due to Friction Force
W_{friction} = \Delta E
Power Equations
P_{avg} = \frac{\Delta W}{\Delta t}
P_{inst.} = \frac{dW}{dt}
Units in Watts
Power of a Constant Force
P = Fv
(dot product)