Question

Two forces P and Q act at such that the resultanat R=P If P is doubled find the angel made by the new resultatnt with respect to the force Q

Answer 1

let a be the angle between the forces P and Q .since their resultant R=P therefore have
P^2=P^2+Q^2+2PQ cos a
0=Q^2+2PQ cosa
cos a = -Q/2P
tan x =2Psin a/Q+2Pcos a
tanx = 2Psin a /Q+2P[-Q/2P]
=2Psin a /0
x=tan^-1infinity
therefore x =90 degree
the new resultant is right angle to angle Q