ax = (vxf - vxi)/∆t, where ∆t =
(tf - ti).
vxf = vxi + ax ∆t.
vx(avg) = (vxf + vxi)/2.
xf - xi = vxi∆t + ½ ax∆t2.
vxf2 = vxi2 + 2ax(xf
- xi).
vx = v0x, ∆x = v0xt, vy = v0y - gt, y = y0 + v0yt - ½ gt2.
F = -kx
W = F·d ,
The work done by a force can be positive or negative. If the component of
the force in the direction of the displacement is positive, the work is
positive, and if the component of the force in the direction of the displacement
is negative, the work is negative.
Kinetic energy: K = ½mv2.
Gravitational potential energy: Ug = mgh (with ground as reference).
Elastic potential energy: Us = ½ kx2.
P = ∆W/∆t
fs≤ μsN, fk = μkN.
Centripetal acceleration: ac = v2/r.
Centripetal force: Fc = mv2/r.
p = mv, F =
∆p /∆t, I
= ∆p = F∆t.
Center of mass: xCM = ∑mixi/M, yCM
= ∑miyi/M, zCM = ∑mizi/M,
M = ∑mi.
ωavg = (θf - θi)/(tf
- ti) = Δθ/Δt.
ωf
= ωi + α(tf -
ti), θf = θi + ωi(tf - ti)
+ ½α(tf - ti)2,
τ = r × F = Iα = ΔL/Δt,
L
= Iω.
Moment of inertia: I = ∑miri2.
Rolling: KEtot = ½mv2
+ ½Iω2, v = rω.