Inertia, mass, acceleration
a1/a2 = m2/m1

Force, mass, acceleration
F = ma

Gravity force
N = mg

Friction force
F_tr = μN

Friction force
F_tr = μmg

Law of universal gravitation
F = G(m1*m2)/r^2

Centripetal acceleration of satellite
a = v^2/(R+h)

Speed (velocity) of satellite
v = saknis(G*M/(R+h))

First cosmic velocity (move in a circular orbit)
v = saknis(gR)

Second (escape) cosmic velocity (overcome gravity)
v = saknis(2gR)

Kepler's Third Law
T1^2/T2^2 = a1^3/a2^3

a1^3/a2^3 = (T1^2*(M1+m1))/(T2^2*(M2+m2))

Free fall acceleration at the earth's surface
g = G*M/R^2

Body weight
P = mg

Body weight: weightlessness
P = m(g-a)

Body weight: overload
P = m(g+a)

Braking (stopping) time
t = mv/F_tr

Braking (stopping) time
t = v/μg

Braking (stopping) distance
s = mv^2/(2*F_tr)

Braking (stopping) distance
s = v^2/(2μg)

Rolling friction force
F_tr = μN/R

Elastic force
F_tampr = k x

Kinetic energy or rotating body
W_k  = J ω^2/2