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Engineering Expert Witness Blog

Published by Philip J. O'Keefe, PE, MLE

Last Build Date: Sat, 22 Apr 2017 01:27:49 +0000


A Pulley Speed Ratio Formula Application

Sat, 22 Apr 2017 01:27:49 +0000

Now, let’s apply Equation (1) to an example in which a blower must deliver a specific air flow to a building’s ventilating system.

Pulley Diameter Determines Speed

Sat, 08 Apr 2017 10:57:52 +0000

    Soon after the first pulleys were used with belts to transmit mechanical power, engineers such as Leonhard Euler and Johann Albert Eytelwein discovered that the diameter of the pulleys used determined the speed at which they rotated.   This allowed for a greater diversity in mechanical applications.   We’ll set up an examination of this phenomenon today. […]

The Difference Between Driven and Driving Pulleys

Fri, 31 Mar 2017 18:56:34 +0000

Our example of a basic mechanical power transmission system consists of two pulleys connected by a drive belt.

Johann Albert Eytelwein, Engineering Trailblazer

Mon, 20 Mar 2017 14:20:10 +0000

Today we’ll introduce his contemporary and partner in science, Johann Albert Eytelwein, a German mathematician and visionary, a true engineering trailblazer...

Leonhard Euler, a Historical Figure in Pulleys

Thu, 09 Mar 2017 22:33:02 +0000

Euler authored his first theoretical essays on the science and mathematics of pulleys after experimenting with combining them with belts in order to transmit mechanical power.

So How Much Friction is Present in our Compound Pulley?

Tue, 28 Feb 2017 14:28:55 +0000

Today we’ll calculate just how much friction is present within the example compound pulley we’ve been working with.

A Compound Pulley’s Numerical Puzzle is Like a Rubik’s Cube

Wed, 15 Feb 2017 16:04:23 +0000

Today we’ll get two steps closer to demonstrating this reality as we work a compound pulley’s numerical puzzle, shuffling equations like a Rubik’s Cube ...

Comparing Work Input to Output in a Compound Pulley

Mon, 06 Feb 2017 19:22:12 +0000

Today we'll begin to numerically demonstrate their inequality by first solving for work output, and later work input.

da Vinci’s Tribometre; a Historical Look at Pulleys and Friction

Sat, 28 Jan 2017 21:16:06 +0000

The tribometre shown in his sketch here is one of history's earliest recorded attempts to understand the phenomenon of friction.

Work Input Does Not Equal Work Output

Mon, 16 Jan 2017 19:45:33 +0000

In other words, work input is not equal to work output in a real world situation in which pulley wheels present a source of friction.