Question

If the resultant of two forces of magnitude P and Q acting at a point at a angle of 60 is root 7 Q , then P/Q is?​

Answer 1

The resultant of two vector P and Q is given by

R=

P

2

+Q

2

+2AQcosθ

⇒

7Q

=

P

2

+Q

2

+2PQ×

2

1

[∵cos60

∘

=1/2]

dividing by Q, we have

7

=

(

Q

P

)

2

+1(P/Q)

⇒7(

Q

P

)

2

+P/Q−6=0

⇒(P/Q+3)(P/Q−2)=0

⇒P/Q=2 ∵P/Q



=−3