A vector has an x component of 5.51 units and a y component of -9.52 units. The angle between the positive direction of the vector and the positive direction of the x-axis is approximately A) 30^o. B) -30^o. C) 60^o. D) -60^o. E) None of these is correct.

Question

Quizplus · Accepted Answer

We can use trigonometry to find the angle between the vector and the positive x-axis. The tangent of the angle is equal to the y-component divided by the x-component: 
tan θ = (-9.52)/5.51 
θ = tan^-1(-9.52/5.51) 
Since the y-component is negative and the x-component is positive, the angle must be in the fourth quadrant where the tangent is also negative. Therefore, the answer is -60°.

A Vector Has an X Component of 5