Question

The components of a vector along the x and y directions are (n+1) and 1 respectively. If the co-ordinate system is rotated by an angle 60⁰, then the components changes to n and 3. The value of n will be,

• A. 3.5
• B. 2
• C. 2.5
• D. 4

Answer 1

The correct option is A

3.5

Length of the vectors doesn't change an rotation.

The magnitude should remain the same.

$\sqrt{{(n+1)}^2+1^2}$ = $\sqrt{n^2+3^2}$ $\Rightarrow$ n = $\frac{7}{2}$ = 3.5