Question

the minimum number of non coplanar forces that can keep a particle in equilibrium is

Answer 1

I would say four forces are necessary. This is just an intuitive answer and I have no formal proof for now.

I just imagined first with two forces (vectors). For two vectors to add up to zero, they must be of same magnitude and opposite direction. Any two vectors will always lie in a plane.

Next, let's make it three vectors. I arbitrarily took one vector along y axis and tried to put another vector in a non xy plane, so that it ends up with a z- component (and the second vector's x component cancels the first). It turns out that the third vector needed to balance the remaining y and z components is such that the three vectors end up being coplanar.

So, four vectors are needed (yes, 4 non coplanar vectors can have a zero resultant)

i hope you understand

Answer 2

Answer:3

Explanation: