Question

In a right hand coordinate system Y-axis and Z-axis are taken as shown in the figure.

Find the direction of the x-axis.

• A. (a) Outward (towards you)
• B. (b) Inward (away from you)
• C. (c) Towards left(your left hand side)
• D. (d) It can be both outward or inward

Answer 1

The correct option is B

(b) Inward (away from you)

The coordinate system we are given is right hand coordinate system. As we have seen, the direction of the axes is determined by the right hand rule in this system. If you curl the fingers of your right hand around the z-axis in the direction of a 90◦ counterclockwise rotation from the positive x-axis to the positive y-axis, then your thumb points in the positive direction of the z-axis. In this case the z-axis is towards the viewer’s right. So the x-axis should be inward for it to be consistent with the rule. Try it yourself. Watch the video for better visualisation.