Question

R is the resultant of vectors A and B. If R=B/√2, then the value of theta is​

Answer 1

Answer:

B _ 45*

EXPLANATION

From the diagram, we have  

A

+  

B

=  

R

 

Thus, R  

2

=A  

2

+B  

2

+2ABcosθ

or, B  

2

/2=A  

2

+B  

2

+2ABcosθ   --- (1)

Also,  

A

 is perpendicular to  

R

 

Thus,  

A

.(  

A

+  

B

)=0 or, A  

2

+ABcosθ=0

which gives, A=−Bcosθ

Put this in (1) to get  

B  

2

cos  

2

θ+B  

2

/2−2B  

2

cos  

2

θ=0

or, cos  

2

θ=1/2 or cosθ=  

2

​  

 

1

​  

, giving θ=45  

0