Key Terms
Definition
A force that opposes the motion of objects that are in contact. Direction: Always opposing relative motion (or tendency
Rearranged
A = F_net / m
Units check
F in N (which is kg x m/s squared), m in kg, a in m/s squared.
Free-fall
When gravity is the ONLY force acting on an object. In reality, air resistance means true free-fall doesn't happen outsi
Weight component perpendicular to slope
W_perpendicular = mg x cos(theta)
Horizontal (x)
F_net_x = ma (if accelerating horizontally) Vertical (y): F_net_y = 0 (if not accelerating vertically)
Weight
W = mg g = 9.8 m/s squared (Earth surface)
Incline components
W_parallel = mg x sin(theta) W_perpendicular = mg x cos(theta)
Elevator scale reading
F_scale = m(g + a) -- accelerating upward F_scale = m(g - a) -- accelerating downward F_scale = mg -- constant velocity