Question

when two forces of magnitude p and q are perpendicular to each other.the resultant is r when they are at 180 to each other their resultant is r/√2ratio of p and q

Answer 1

p^2+q^2+2pqcos90°=r^2
(cos90°=0)
p^2+q^2=r^2......I
and
p^2+q^2+2pqcos180°=r^2/2
(cos180°=1)
p^2+q^2+2pq=r^2/2
now,
pq=1/2
so, p+q=r/root2