(a) primary forces and couples must be balanced

(b) secondary forces and couples must be balanced

both (a) and (b)

none of these

P = W tan(? - ?)

P = W tan(? + ?)

P = W tan(? - ?)

P = W cos(? + ?)

sliding pair

rolling pair

lower pair

higher pair

Right

Wrong

(a) the algebraic sum of the primary forces must be equal to zero

(b) the algebraic sum of the couples about any point in the plane of the primary forces must be equal to zero

both (a) and (b)

none of these