Let `vecA and vecB` be the two vectors of magnitude 10 unit each. If they are inclined to the X-axis at angles `30^@ and 60^@` respectively, find the resultant.

Answer

A, B, C, D

Explanation

`R = [(10cos 30^@)hati+(10cos 60^@) hatj]`
`+[(10 cos 60^@)hati+(10cos30^@) hatj]`
`=10(cos30^@ + cos 60^@) hati + 10(cos 60^@ + cos 30^@)hatj`
`=10(2cos 45^@ cos 15^@) hati + 10(cos 45^@ cos 15^@ hatj`
`=R_xhati +R_yhatj`
Here, `R_x =R_y = 10sqrt2 cos 15^@`
`:. |R| = sqrt(R_x^2 +R_y^2 = 20cos 15^@`
since `R_x = R_y`, therefore,` theta = 45^@` .