Game of Cones

Geometry Level 2

You're operating a cone-cutting device with the high-energy laser beam. This laser ray is parallel to the sliding belt, and its generator is fixed at all time.

You may simply place a cone on its base or may tilt it a little with a machinery arm. However, if the cone is tilted over the angle θ \theta (within the cone), it will be toppled to the belt as shown in the picture.

Which conic section is visually impossible to achieve by this machine? (Assume that all the cones stay still enough to be cut.)

Circle Hyperbola Ellipse Parabola

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

1 solution

Andrew Ellinor
Oct 29, 2015

Let's suppose that it would be sufficient to create just one branch of a hyperbola (after all, you would need two cones to achieve a hyperbola). In order for this to happen, the axis of the cone must be parallel to the conveyor belt that the cone sits on. Oriented upright, the cone will create a circle. Tilted slightly without tipping, the cone's cross-section will be an ellipse. But if it topples over, the cone's axis will point into the conveyor belt and the cross-sectional cuts will be parabolic.

In order to create the hyperbolic branch desired, the cone would need to be held at an angle that exceeds what is allowed before the cone topples over, so the hyperbola cannot be achieved.

Fun problem!

Thank you for your solution. It's fun thinking of it, too! ;)

Worranat Pakornrat - 5 years, 7 months ago

I got everything, but what is a hyperbola?

Debmeet Banerjee - 5 years, 7 months ago

Log in to reply

It's a conic section that goes beyond the parabolic plane. The most obvious example is when you try cutting the cone vertically parallel to its vertical axis. One example of the graph is: x^2 - y^2 = 1.

Worranat Pakornrat - 5 years, 7 months ago

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...