Home
Class 12
PHYSICS
Two vectors vec A and vecB have equal ma...

Two vectors `vec A and vecB` have equal magnitudes.If magnitude of `(vecA+vecB)` is equal to n times of the magnitude of `(vecA-vecB)` then the angle between `vecA and vecB` is :-

A

`sin^(-1)[(n-1)/(n+1)]`

B

`sin^(-1)[(n^(2)-1)/(n^(2)+1)]`

C

`cos^(-1)[(n-1)/(n+1)]`

D

`cos^(-1)[(n^(2)-1)/(n^(2)+1)]`

Text Solution

Verified by Experts

The correct Answer is:
D
`sqrt(A^(2)+A^(2)+2A^(2)cos theta)=n sqrt(A^(2)+A^(2)-2A^(2)cos theta)`
`2A^(2)(1+cos theta)=2A^(2)n^(2)(1-cos theta)`
`(1+cos theta)/(1-cos theta)=n^(2)`
`cos theta = (n^(2)-1)/(n^(2)+1) rArr theta=cos^(-1)((n^(2)-1)/(n^(2)+1))`
Promotional Banner

Similar Questions

Explore conceptually related problems

Two vectors vecA" and "vecB have equal magnitudes. If magnitude of vecA+vecB is equal to n times the magnitude of vecA-vecB , then the angle between vecA" and "vecB is :-

If |vecA xx vecB| = |vecA*vecB| , then the angle between vecA and vecB will be :

Can the magnitude of vecA -vecB be equal to vecA+vecB ?

The resultant of two vectors vecA and vecB is perpendicular to the vector vecA and its magnitude is equal to half of the magnitude of the vector vecB . Find out the angles between vecA and vecB . .

The resultant of two vectors vecA and vecb is perpendicular to the vector vecA and its magnitude is equal to half the magnitude of vector vecB . The angle between vecA and vecB is

If |veca.vecb|= |veca xx vecb| , then the angle between veca and vecb is

If vecA.vecB = |vecA xx vecB| , find angle between vecA and vecB .

A magnitude of vector vecA,vecB and vecC are respectively 12, 5 and 13 units and vecA+vecB=vecC then the angle between vecA and vecB is

The magnitudes of vectors vecA,vecB and vecC are 3,4 and 5 units respectively. If vecA+vecB= vecC , the angle between vecA and vecB is