Question

We need to apply vector math sometimes in the calculation of the stability of equilibrium configurations. So the coordinate of the Force vector AB is A (2, 0, 2) and B (-2, 3.46, 3). It has a magnitude of 750N. Which is the best Cartesian representation of the vector AB?

(a) -557i + 482j + 139k N

(b) -557i – 482j + 139k N

(c) -557i + 482j – 139k N

(d) 557i – 482j – 139k N

I got this question during an interview.

My query is from Stability of Equilibrium Configurations in portion Principle of Virtual Work of Engineering Mechanics

Answer 1

The correct answer is (a) -557i + 482j + 139k N

Easy explanation: First try to make the unit vector of AB. Then you will get the Cartesian form of a unit vector after that just multiply 750 scalar quantity with it. Which means you are first taking out the desired direction and then multiplying the scalar to get the desired vector in the desired direction.