2. Questions Bank
  3. JEE Main & Advanced
  4. Mathematics
  5. Vector Algebra

JEE Main & Advanced Mathematics Vector Algebra Question Bank Modulus of vector Algebra of vectors

  • question_answer
    The points with position vectors \[60\,\mathbf{i}+3\,\mathbf{j}\], \[40\,\mathbf{i}-8\mathbf{j},\], \[a\,\mathbf{i}-52\,\mathbf{j}\] are collinear, if \[a=\]                                                             [RPET 1991; IIT 1983; MP PET 2002]

    A) 40

    B) 40

    C) 20          

    D) None of these

    Correct Answer: A

    Solution :

    If the given points be A, B, C, then \[\overrightarrow{AB}=k(\overrightarrow{BC})\] \[\Rightarrow -20\mathbf{i}-11\mathbf{j}=k\left[ (a-40)\mathbf{i}-44\mathbf{j} \right]\] On comparing, \[-11=-44k\Rightarrow k=\frac{1}{4}\] And \[-20=\frac{1}{4}(a-40)\Rightarrow a=-40.\]              


You need to login to perform this action.
You will be redirected in 3 sec spinner