Velocity Acceleration X and Y components of initial velocity vy = vocosθ vx = vosinθ Resultant force Gravitational force Torque r = distance between fulcrum and force θ = angle between force and lever arm Centripetal force Centripetal acceleration Kinetic friction μk = coefficient of kinetic friction Fn = normal force static friction  anything above that is kinetic friction Potential energy Total mechanical energy  = constant When there's no friction/air resistance Work done by non conservative forces Work W = Fdcosθ Power   J/s = watts Work Energy theorem Momentum units: kg m/s Impulse Elastic collisions - objects dont stick objects dont stick. Momentum and KE are conserved. Inelastic collisions Kinetic energy is lost in the form of heat, light or sound therefore final KE is less that initial. Momentum is conserved Completely Inelastic collisions Objects stick together Kinetic energy is not conserved.  Momentum is conserved, objects have the same velocity after combining.