Question

Two vectors $A=3$ and $B=4$ are perpendicular. Resultant of both these vectors is $R.$ The projection of the vector $B$ on the vector $R$ is

• A. $3.2$
• B. $2.4$
• C. $5$
• D. $1.25$

Answer 1

The correct option is A $3.2$


The projection of $B$ on $R$
$=B\cos \theta$
From the diagram
$\cos \theta =\frac{B}{R}=\frac{4}{5}$
Hence the projection
$=4\times \frac{4}{5}=3.2$