Simple pendulum subject to a driven force

[LCSphysicist]

Homework Statement

All below

Relevant Equations

All below

The problem is how to construct the right diagram of forces actually

Unfortunately, the Fo*cos acting on the ball will not carry the g/l of the solution

-mg*sin(´p) + (-bv) + (Fo*cos(wt)*cos(p)) = mx''
Fo*cos(wt) = mx'' + mg*x/l + bv

 

[haruspex]

Homework Statement:: All below
Relevant Equations:: All below

View attachment 266128
The problem is how to construct the right diagram of forces actually

View attachment 266129

Unfortunately, the Fo*cos acting on the ball will not carry the g/l of the solution

-mg*sin(´p) + (-bv) + (Fo*cos(wt)*cos(p)) = mx''
Fo*cos(wt) = mx'' + mg*x/l + bv

You do not care what force is applied at the point of suspension. You only care where that point is at time t, and how that affects the angle of the pendulum.