Translational Equilibrium

A body is in translational equilibrium when the vector sum of forces acting on it is zero. As a result, the body stays in one location.

Moment (or torque) = F x perpendicular distance to pivot point

A body is in rotational equilibrium when the sum of clockwise moments = sum of counter-clockwise moments. As a result, the body does not rotate.

Momentum = mv

Momentum is a vector quantity, meaning it has direction as well as magnitude.

S mv before collision = S mv after collision

In an elastic collision, KE is conserved. In an inelastic collision, some or all of the KE is converted to sound, light, heat, and so forth.

Impulse = change in momentum
= D (mv)
= mD v

Since F = ma = mD v/t
mDv = Ft
or impulse = Ft

PE = mgh

KE = ½mv²

Work done = Fd

Where F is force and
d is distance

Power is the rate at which work is done

Power = Fd/t = Fv