Heat Islands not Just a City Thing
We’ve all heard about the heat island effect around large cities. Concrete, buildings, and asphalt absorb solar radiation and then re-emit it to the air. It makes cities a few degrees warmer, particularly on sunny days. But the same effect happens around data centers too. Data centers often draw hundreds of megawatts of electricity, and […]
FEATURED TESTIMONIAL – “Dr. Tom Does a Sterling Job”
“If it wasn’t for Dr Tom’s encouraging and clarifying teaching style, I doubt I’d ever have the courage take on the Thermal and Fluids Systems PE exam. In fact, Thermodynamics and Heat Transfer were the areas in which I was struggling the most in college, some twenty years ago. Dr Tom’s course made these ‘difficult’ […]
Learn to Solve Dynamics Problems Correctly
Watch our video! This presentation looks at the classic motion of a vehicle moving along a level road, where it could be speeding up or slowing down. In the example presented, the vehicle is slowing down due to its brakes, and in fact, we are told the wheels lock up. What is required in the […]
Making Heat Pumps Better with a Common Ingredient
Heat pumps are a great way to use the power (and heat) of thermodynamics to move heat from a cold space to a hot space. Their Coefficient of Performance (COP) makes them a better option than fossil fuels in some climates. Renewable energy like solar, can also reduce the carbon footprint. However, the biggest problem […]
Welding Symbols
Watch our video! One of the most important standards in machine design are those specified by the American Welding Society. In one symbol critical information about the required weld is provided, such as location of the weld, type of weld, and size of the weld. If there are two sides to the connection, the symbol […]
MECHANICAL PE EXAM TIP – Units, Units Units!!!
If I wasn’t Dr. Tom, I’d be Dr. Units. I cannot tell you how many times units are the reason someone gets the wrong answer to a problem. It might be as simple as inches needed to be converted to feet, or the other way around. Or, it is a combination of units like gallons per minute […]
Turn Complex Motion into Clear and Understandable Solutions
Watch our video! One of the most common and useful mechanisms in machine dynamics is the “slider-crank.” It has three elements: the “slider”, the “crank”, and the “connecting rod.” The slider is in “pure translation”, moving back and forth in a straight path. The crank is in “pure rotation”, moving in perfect circular motion. Then, […]
The Dr. Tom Method – The Perfect System to Pass the PE Exam
At Dr. Tom’s Classroom, we’ve worked hard to create the perfect system to help Mechanical engineers pass the PE Exam and become Professional Engineers. With PE Exam Review courses for all three Mechanical PE Exams (HVAC & Refrigeration, Machine Design & Materials, and Thermal & Fluid Systems), we can help you pass the PE Exam. […]
Simplify Distributed Load Analysis With This Proven Method
Watch our video! Distributed loads appear in a great variety of problems, the most common being loadings on beams. This video shows how to replace the three most common distributed loads with a single force at a single location. These loadings include rectangular, triangular, and trapezoidal. Note that a trapezoidal loading can be treated as […]
The Automotive Differential – lots and lots of gears!
While being absorbed watching videos on a popular social media site, a video appeared talking about the need for a differential on your car. It was very short and didn’t provide a satisfactory explanation of how the design evolved. I searched the internet and discovered a very unique discussion of the principles involved. Surprisingly, it […]
