Question

A vector has component along the X-axis equal to $25$ unit and along the Y-axis equal to $60$ unit. Find the magnitude of the vector.

• A. $60$
• B. $65$
• C. $70$
• D. $75$

Answer 1

The correct option is B $65$

The given vector is the resultant of two perpendicular vectors, one along the X-axis of magnitude $25$ unit and the other along the Y-axis of magnitude $60$ units.

Let the resultant has a magnitude $A$ given by, $A=\sqrt{{25}^2+{60}^2+2\times 25\times 60\cos {90}^{\circ }}$
$\Rightarrow A=\sqrt{{25}^2+{60}^2}=65$