Question

plz give answer fast..

Answer 1

let the two forces be a & b and the resultant of these at angle 90 be c and that of 120 be d
then c=5=√[a^2+b^2+2abcos90
25 = a^2+b^2
&
d=√[a^2+b^2-2abcos120]
√13= √[a^2+b^2-ab]
13=a^2+b^2-ab
now substitute a^2+b^2 = 25 here
so 13= 25 -ab
ab= 12
now we can solve for a and b but before that this question has options so let us check the option whose product is 12
clearly C) 3,4 has the product 12
hence the answer is C