How many types of friction is there?

In total there are 4 distinct forces: The electromagnetic force, the weak nuclear force,

strong nuclear force, and gravitation.

Recently, the electromagnetic force and the weak force has been combined into the

electroweak force. Physicists are aiming to "unify" the other two forces like this.

Answer2:

Forces are the first derivative of energy. Energy is a Quaternion quantity having a scalar/Boson S part and a vector/Fermion V part or a Boson part and a Fermion part.

The energy is W = S + V = [s,V]

The forces is the first derivative

Force F = [d/dr,Del] [s,V] = [ds/dr -Del.V, dV/dr + Del s + DelxV]

There are Five Forces;

1. The Centripetal scalar force: ds/dr

2. The Centrifugal scalar force: -Del.V

3. The Tangent vector force: dV/dr

4. The Gradient vector force: Del s

5. The Curl vector force: DelxV

For example the five forces of Gravity Forces are:

W = -mGM/r + cP = -vh'/r + cP

where the vector force is the Momentum energy cmV=cP, the "Dark Energy"!

F= [d/dr,Del] [-vh'/r, cP] = [vp/r -cDel.P, cdP/dr - Del vh'/r + cDelxP]

F = [vp/r - cp/r cos(P), -cp/r 1P + vp/r 1R + cp/r sin(P) 1RxP]

1. centripetal force: vp/r this is the gravitational attraction force.

2. centrifugal force: -cDel.P= -cp/r cos(P) this is the "Cosmos Divergence" force.

3. tangent vector: cdP/dr = cdP/cdt = dP/dt = mdV/dt

4. Gradient vector: Del -mGM/r = mGM R/r3 = mGM/r2 1R = vp/r 1R

5. Curl Vector: cDelxP = cp/r sin(P) 1RxP this is the circulation/Transverse vector.

At the Boundary/Stationary 0=F Condition there are only 4 forces,

the Curl is zero, 0=DelxV and Newton's Equal and Opposite forces is true.