Home
Class 12
PHYSICS
If veca+vecb=vec c and a+b=c, what is th...

If `veca+vecb=vec c` and a+b=c, what is the angle between `veca` and `vecb` ?

A

`90^(@)`

B

`180^(@)`

C

`120^(@)`

D

zero

Text Solution

Verified by Experts

The correct Answer is:
D

Here `veca+vecb=vecc` and c=a+b
Let `theta` be angle between `veca` and `vecb` .
`:. c = sqrt(a^(2)+b^(2)+2abcostheta)`
`a+b= sqrt(a^(2)+b^(2)+2ab cos theta)`
Squaring both sides we get
`(a+b)^(2) =a^(2)+b^(2) +2abcostheta`
`a^(2)+b^(2)+2ab=a^(2)+b^(2)+2abcostheta`
`2ab-2abcos theta=0 or 1-costheta=0`
`cos theta=1 or theta =cos^(-1) (1) =0^(@)`
Doubtnut Promotions Banner Mobile Dark
|

Topper's Solved these Questions

  • KINEMATICS

    MTG-WBJEE|Exercise WB JEE WORKOUT ( CATEGORY 3 : One or More than One Option Correct Type (2 Marks))|10 Videos
  • KINEMATICS

    MTG-WBJEE|Exercise WB JEE Previous Years Questions (CATEGORY 1 : Single Option Correct Type (1 Mark) )|9 Videos
  • KINEMATICS

    MTG-WBJEE|Exercise WB JEE Previous Years Questions (CATEGORY 3 : One or More than One Option Correct Type (2 Marks) )|1 Videos
  • HEAT AND THERMAL PHYSICS

    MTG-WBJEE|Exercise WB JEE PREVIOUS YEARS QUESTIONS|15 Videos
  • KINETIC THEORY OF GASES

    MTG-WBJEE|Exercise WB JEE PREVIOUS YEARS QUESTIONS (MCQ)|7 Videos

Similar Questions

Explore conceptually related problems

If veca+vecb=vec c and c=sqrt(a^2+b^2) . What is the angle between veca and vecb ?

If veca and vecb are two vectors such that |veca xx vecb|= veca.vecb , then what is the angle between veca and vecb ?

Knowledge Check

  • If |veca - vecb|=|veca| =|vecb|=1 , then the angle between veca and vecb , is

    A
    `pi/3`
    B
    ` ( 3pi)/4`
    C
    ` pi/2`
    D
    0
  • If |veca.vecb|= |veca xx vecb| , then the angle between veca and vecb is

    A
    ` 0^(@)`
    B
    ` 180^(@)`
    C
    ` 150^(@)`
    D
    `45^(@)`
  • If vecA+ vecB = vecC and A+B+C=0 , then the angle between vecA and vecB is :

    A
    0
    B
    `(pi)/(4)`
    C
    `(pi)/(2)`
    D
    `pi`
  • Similar Questions

    Explore conceptually related problems

    What is the angle between (vecA+vecB) and (vecA-vecB) ?

    If three unit vectors veca, vecb and vecc " satisfy" veca+vecb+vecc= vec0 . Then find the angle between veca and vecb .

    If veca +vecb +vecc =vec0, |veca| =3 , |vecb|=5 and |vecc| =7 , then the angle between veca and vecb is

    If veca,vecb are two unit vectors such that |veca + vecb| = 2sqrt3 and |veca -vecb|=6 then the angle between veca and vecb , is

    If veca and vecb are unit vectors such that (veca +vecb). (2veca + 3vecb)xx(3veca - 2vecb)=vec0 then angle between veca and vecb is