Question

You are holding an elliptical serving platter. How would you need to travel for the serving platter to appear round to another observer?

Short answer

answer is not given in the drive.

Step-by-step solution

Concept of the serving platter to appear round to another observer       

For the elliptical serving platter to appear round, it must be shrunk along the direction of the major axis. To do so, you will need to hold the serving platter and travel, say, to the right at a specific speed u relative to another observer at rest. As shown in Fig. 1, the serving platter must be oriented in such away that its major axis is parallel to the direction of your motion. If you are to attain just as the right speed u relative to the stationary observer, you and your serving platter will appear, to this observer, shrunk along the direction of motion just as to look round (the major axis of the elliptical serving platter will shrink to the size of its minor axis).

Diagrammatic view