Question

1. A vector A makes an angle of 20° and B makes an angle
of 110° with the X-axis. The magnitudes of these vectors
are 3 m and 4 m respectively. Find the resultant.and the angle
​

Answer 1

If two vector A and B make an angle ∅ between them then resultant is

$(R {)}^{2} = {A}^{2} + {B}^{2} + 2AB \cos(∅)$

A and B make a angle 20⁰ and 110⁰ with a x axis angle between them is 90⁰

$(R {)}^{2} = {3}^{2} + {4}^{2} +2×4×cos9 {0}^{0} =9+16+0 = 25$

$\cos{90}^{0}=0$

$=> R \sqrt{25} = 5$

angle btween R and A is 53⁰ so angle make by R with x axis

50⁰+20⁰=73⁰

Hence the resultant is 5