Question

In the figure given below, with F1 = 60j + 80k and F2= 50i -100j + 100k, what is the value of β? (β is the angle made by the resultant vector with the y-axis )

(a) 76˚

(b) 102˚

(c) 19˚

(d) 130˚

The question was asked during an interview for a job.

My question is based upon Cartesian Vectors topic in division Force Vectors of Engineering Mechanics

Answer 1

Correct answer is (b) 102˚

The explanation is: Just add the two vectors in their Cartesian form only. After that you will get the resultant vector in the Cartesian form. After that just divide the y-axis component’s magnitude by the resultant of the vector. You will get cosβ.