Question

If vectors A and B have magnitude 5 & 12 units respectively and their resultant is 13
units, find the angle made by resultant with vector A.​

Answer 1

Explanation:

A+B=R

B=r-a

$b {}^{2} = a {}^{2} + r { }^{2} - 2ar \cos(theta)$

144=25+169+130 cos(theta)

144-194=130cos(theta)

50=130cos(theta)

Cos(theta)=50/130

Theta =cos(inverse) 5/13