Two vectors inclined at an angle (\theta) have magnitude 3 N... | Physics | SolveeIt | Solveeit

Today, August 18

Question

Two vectors inclined at an angle $\theta$ have magnitude 3 N and 5 N and their resultant is of magnitude 4 N. The angle $\theta$ is

A

$90^\circ$

B

$cos^{-1}\left(\frac{4}{5}\right)$

C

$cos^{-1}\frac{3}{5}$

D

$cos^{-1}\left(-\frac{3}{5}\right)$

Answer

$cos^{-1}\left(-\frac{3}{5}\right)$

Explanation

Solution

If it possible when the angle between 3 & 5 is greater than $90^{\circ}$ $R = \sqrt{P^2 + Q^2 + 2PQ \, \cos \,\theta}$