Plane Puzzle – My Solution

This post is in response to a puzzle posted by a friend of mine.

The puzzle is as follows:

“If a plane is placed on a giant treadmill, and the treadmill is programmed to automatically match the plane’s forward speed (in the opposite direction), can the plane take off?”

Before I begin to solve the solution, here are a few assumptions: Continue reading

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Math/Critical Thinking Puzzle – 8/30/12

Here’s a nifty little math puzzle I came up with recently.

Preliminary Information

There are three sets of parallel lines on a 2D surface (plane). Each set contains an infinite number of lines, and each line is infinite.

The parallel lines in each set Continue reading

Origami Buckyball

I’ve begun work on a rather largish buckyball. Below is a section that will end up composing about 1/12 of the finished thing. There will be 12 sections of 4 colors (yellow, blue, green and red), or 3 sections of each color. I’m not exactly sure how I will connect these sections; I suppose I’ll find out when/if the time comes.
Image

Yes, that is an Escher in the background.

Pendulum Wave Demonstration With Matlab

Video

I’ve decided to build a pendulum wave and write an Instructable to document the process.

In the meantime, here’s a matlab demonstration showing how I hope it will behave. Matlab function is posted after the video.


%Created by Eric Cox - https://ericboy.wordpress.com - 5/17/2012

function [] = PWT(n,f,df,t)

%This function plots pendulum wave motion as seen from the top view.
%
% n is the number of pendulums, f is the frequency of the first pendulum
% in the wave, df is the incremental change in frequency between pendulums
% (added), t is the time to display the animation

%set initial time to zero.
t_n=0;

%preallocate lengths of matrices.
y=(1:n);
x=(1:n);

while (t>t_n)

%for each value in x,y matrices, populate with value at current t.
for j=1:n
x(j)=j;
y(j)=sin(2*pi*(f+(j)*df)*t_n+pi/2);
end

%Plot pendulum wave
plot(x,y,’o’,’MarkerEdgeColor’,’k’,…
‘LineWidth’,2,…
‘MarkerFaceColor’,’b’,…
‘MarkerSize’,11);

%Define axis
axis([0 n+1 -1.5 1.5]);

%Increment loop time
t_n=t_n+1/30;

%Animation delay
pause(1/30);

end

That Awkward Moment

That awkward moment when you are waiting outside your professor’s door, listening to him yell at your classmate about the exact same issue with the exact same problem that you are waiting to discuss.

That awkward moment when you’re sitting in Starbucks listening to your headphones, and then realize that the headphones are not plugged in to your computer. Everyone in the coffee shop makes an effort to avoid looking in your direction as you realize your mistake and fumble around with the headphones jack.