Do not forget the weight of the ball
The equilibrium is given by
You can do the projection of this vectorial equality on any axis, for instance on each plane
The diagram (attached) shows a small ball of mass 2 kg, resting in the horizontal groove between two smooth planes inclined 20 degrees and 40 degrees to the horizontal. Find the magnitudes of the contact forces P and Q.
I know I have to resolve the forces in one direction but I'm stuck cause I don't have any angles.
Since it's in equilibrium the sum of all the forces in each direction is equal.