FREE Mechanical Videos

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MECHANICAL CATALOG

To Help You Make that Leap of Understanding.

I have taught every mechanical engineering undergraduate course, and I have always enjoyed finding a way to help my students understand mechanical concepts and apply them. That’s why I’m offering these free videos, to help people make that leap of understanding.

I originally created most of these videos as I come across topics in the MERM and NCEES Practice Exam that needed greater clarification. From the response we have received to them, the videos have turned out to be valuable to anyone studying these concepts. The video on Distributed Loads has been watched over 50,000 times and the other top videos on Slider-Crank, Vehicle Dynamics, Zero-force Members and other topics have been watched many thousands of times.

I plan to keep adding new free videos, and I hope they help you understand these topics better in ways that improve your success in your school work and your career.

– Dr. Tom

Guy listening at computer DTC logo

“Many of the prep course options seemed a little impersonal to me and offered very few samples of the course content that they offer. I noticed Dr. Tom was much more generous with his free content and explained himself very clearly. I was pretty much sold after I saw his videos on exam strategy. His course requires a lot of time and work, but he had a solid plan and he was there with us every step of the way. By the time exam day came around, I was very prepared and felt I had a realistic chance of passing this exam.

– Brian, PE, Taylor Machine Works, Starkville, Mississippi

Sample lessons from DTC Mechanical PE EXAM REVIEWS

These are lesson videos from our Mechanical PE Exam Review lessons for the new CBT exam format. They give you a good idea what the lessons are like.

HVAC & REFRIGERATION EXAM - SAMPLE LESSONS

Machine Design & Materials Exam - Sample Lessons

Thermal & Fluid Systems Exam - Sample Lessons

What the MERM Doesn’t Tell You Videos

DYNAMICS

The MERM has some major gaps and problematic approaches to various topics. The goal of these videos is to address these tricky concepts that are important to understand if you are taking any of the Mechanical Engineering PE Exams.

STATICS

MACHINE DYNAMICS

NCEES PE Mechancial Practice Exam Problems (Solution Tips)

The goal of these videos is to address selected problems on the NCEES PE Mechanical Practice Exams that have solutions that may cause confusion.
 
You can purchase the NCEES Practice Exam for the PE exam you are taking at

 

HVAC & REFRIGERATION- NCEES PRACTICE EXAM

For PE Mechanical HVAC & Refrigeration Practice Exam Problem 2, the NCEES solution uses a very unfamiliar equation to calculate the required pump input power. And it also uses some cumbersome units and their conversions. First calculate the horsepower required from Bernoulli, then apply the pump and motor efficiencies to obtain the required input power to the pump. From there the operating cost is a simple calculation. Give this problem a try, then watch the video, and I hope you find it helpful. – Dr. Tom
 
You can purchase the NCEES Practice Exam for the PE exam you are taking at: https://account.ncees.org/exam-prep/.
For PE Mechanical HVAC & Refrigeration Practice Exam Problem 13, the NCEES solution is very confusing. First, the problem says both the AHU-3 and the system bypass are at the same level, 75 feet, which doesn’t correlate with the given figure and isn’t needed anyway. Second, each AHU and it control valve are in parallel with the rest of the system, so the pressure drops must be equal. The rest is converting a pressure head to pressure. Give this problem a try, then watch the video, and I hope you find it helpful. – Dr. Tom
 
You can purchase the NCEES Practice Exam for the PE exam you are taking at: https://account.ncees.org/exam-prep/.
For PE Mechanical HVAC & Refrigeration Practice Exam Problem 27, the NCEES solution suggests that the enthalpy of the mixture is simply an average of the enthalpies of the incoming water and steam. Not showing how this equation was determined is very confusing.. And a figure like the one I show in the video would have been very helpful. Give this problem a try, then watch the video, and I hope you find it helpful. – Dr. Tom
 
You can purchase the NCEES Practice Exam for the PE exam you are taking at: https://account.ncees.org/exam-prep/.
For PE Mechanical HVAC & Refrigeration Practice Exam Problem 56, this problem involves a closed feedwater heater, basically a heat exchanger where the two fluids do not mix. In the statement of the problem, all the enthalpies but one are given, which is fortunate as double interpolation would most likely have been involved with state (1) of the incoming steam. However, these enthalpies are substituted into an equation whose origin is unexplained. Also, there is a lack of units shown in this equation except in the final answer. Give this problem a try, then watch the video, and I hope you find it helpful. – Dr. Tom
 
You can purchase the NCEES Practice Exam for the PE exam you are taking at: https://account.ncees.org/exam-prep/.

MACHINE DESIGN & MATERIALS - NCEES PRACTICE EXAM

For PE Mechanical Machine Design & Materials Practice Exam Problem 12, the NCEES solution begins with an equation that has been the source of a great many questions and confusion by previous participants as to its origin. In this video, I show how this equation comes to define the problem. Give this problem a try, then watch the video, and I hope you find it helpful. – Dr. Tom

You can purchase the NCEES Practice Exam for the PE exam you are taking at: https://account.ncees.org/exam-prep/.
 

For PE Mechanical Machine Design & Materials Practice Exam Problem 28, the NCEES solution is fine, except there appears to be an inconsistency between the wording in the statement of the problem and the information shown in the solution as to what value of the shear force should be used.

 
You can purchase the NCEES Practice Exam for the PE exam you are taking at: https://account.ncees.org/exam-prep/.
For PE Mechanical Machine Design & Materials Practice Exam Problem 53, the NCEES solution is fine, however it is unnecessary to draw the entire shear force diagram and then use similar triangles. Also, there is a typo on the left side of the shear force diagram shown in the NCEES solution where 120 in should be 120 lb. Give this problem a try, then watch the video, and I hope you find it helpful. – Dr. Tom
 
You can purchase the NCEES Practice Exam for the PE exam you are taking at: https://account.ncees.org/exam-prep/.
For PE Mechanical Machine Design & Materials Practice Exam Problem 61, the NCEES solution begins with an equation that causes confusion as to its origin. In this video, I show how this equation comes to define the problem.
 
Give this problem a try, then watch the video, and I hope you find it helpful. – Dr. Tom
 
You can purchase the NCEES Practice Exam for the PE exam you are taking at: https://account.ncees.org/exam-prep/.

THERMAL & FLUIDS SYSTEMS - NCEES PRACTICE EXAM

For PE Mechanical Thermal & Fluid Systems Practice Exam Problem 14, the NCEES solution suggests that the enthalpy of the mixture is simply an average of the enthalpies of the incoming water and steam. Not showing how this equation was determined has been very confusing and the source of many questions by previous participants. And a figure like the one I show in the video would have been very helpful. Give this problem a try, then watch the video, and I hope you find it helpful. – Dr. Tom
 
You can purchase the NCEES Practice Exam for the PE exam you are taking at: https://account.ncees.org/exam-prep/.
For PE Mechanical Thermal & Fluid Systems Practice Exam Problem 19, the NCEES solution is very confusing. First, the problem says both the AHU-3 and the system bypass are at the same level, 75 feet, which doesn’t correlate with the given figure and isn’t needed anyway. Second, each AHU and it control valve are in parallel with the rest of the system, so the pressure drops must be equal. The rest is converting a pressure head to pressure. Give this problem a try, then watch the video, and I hope you find it helpful. – Dr. Tom
 
You can purchase the NCEES Practice Exam for the PE exam you are taking at: https://account.ncees.org/exam-prep/.
For PE Mechanical Thermal & Fluid Systems Practice Exam Problem 28, the primary confusion with the NCEES solution has been that the given diagram of the fan and compressor does not show clearly that there are two paths for the air, one through the compressor and one through the fan and around the compressor. The NCEES issued an errata diagram for the 2016 edition which I think helped resolve the confusion, however the 2019 edition has a different diagram that I believe gives the impression that the air from the exit of the fan goes into the inlet of the compressor which it does not. Both the fan and compressor see the same inlet conditions. Also, the NCEES solution reflects that constant specific heats were to be used. That should have been stated explicitly. Give this problem a try, then watch the video, and I hope you find it helpful. – Dr. Tom
 
You can purchase the NCEES Practice Exam for the PE exam you are taking at: https://account.ncees.org/exam-prep/.
For PE Mechanical Thermal & Fluid Systems Practice Exam Problem 30, the NCEES solution is very confusing. This is a perfect application of the AE form of the Bernoulli Equation. The given “head” is the difference in the stagnation pressure and the pressure at another point in the flow, divided by the specific weight. However, the head is given in terms of water. And note that the specific weight of the air, not density, is given. ( lbm/ft3 = lb/ft3 ) Give this problem a try, then watch the video, and I hope you find it helpful. – Dr. Tom
 
You can purchase the NCEES Practice Exam for the PE exam you are taking at: https://account.ncees.org/exam-prep/.
For PE Mechanical Thermal & Fluid Systems Practice Exam Problem 72, there are a couple of specialized terms used in the statement of the problem: “bottom blowdown” and “flash tank.” Then the “flash tank” is called the “heat exchanger.” Very confusing. The problem is based on the principle that the heat lost from the bottom blowdown to create steam in the flash tank must be equal to the heat gained by the water entering the flash tank that is converted to steam. Give this problem a try, then watch the video, and I hope you find it helpful. – Dr. Tom
You can purchase the NCEES Practice Exam for the PE exam you are taking at: https://account.ncees.org/exam-prep/.
For PE Mechanical Thermal & Fluid Systems Practice Exam Problem 76, the NCEES solution provides the correct answer, however the steps are not clear and not in the order they should be. In fact, the term in the denominator of the expression for the thermal efficiency is incorrect. Also, there are virtually no units provided. And the assignment of a value of “1” to one of the quantities has been the source of many questions by previous participants. Give this problem a try, then watch the video, and I hope you find it helpful. – Dr. Tom
 
You can purchase the NCEES Practice Exam for the PE exam you are taking at: https://account.ncees.org/exam-prep/.

Mechanical Engineering Fundamentals Videos

These videos review several fundamental topics of Mechanical Engineering that are likely to appear on the Mechanical PE Exam.

This video has been quite popular and is a great place to begin your review of Fluid Mechanics, starting with Fluid Properties, including a discussion of viscosity for Couette and Poiseuille Flows.

This video on Fluid Properties was originally the second of three-part Study Strategy series on Fluid Mechanics topics found on the Mechanical PE Exam. With the many changes in the PE Exam since this was recorded, the first video was made obsolete, so it is no longer available.

This video on the Continuity Equation was originally the third of three-part Study Strategy series on Fluid Mechanics topics found on the Mechanical PE Exam. With the many changes in the PE Exam since this was recorded, the first video was made obsolete, so it is no longer available.

I suggest that you watch my Fluid Properties video before watching this one. This video continues our review Fluid Mechanic Fundamentals, focusing on the Continuity Equation. I begin with a discussion on the Types of Fluid Flow. Please let us know if you find it helpful. – Dr. Tom

In this video on Heat Exchangers, I go over LTMD Correction and the epsilon NTU method. It’s an important topic on the Thermal & Fluid Systems Mechanical PE Exam.

This video was originally a lesson in my review for the Thermal & Fluid Systems Mechanical PE Exam, and you’ll find lots more lessons like this in my review.

In this video on Welding Symbols, I go over the basics of using these symbols, based on the American Welding Society Standards. It’s an important topic to understand for the Machine Design & Materials Mechanical PE Exam.

This video was originally a lesson in my review for the Machine Design & Materials Mechanical PE Exam, and you’ll find lots more lessons like this in my review.

“Dr. Tom’s 20-week Thermal Fluid System course is the best option on the market, hands down. During my preparation, I was fortunate to have access to two other mainstream services. After a few weeks of using them concurrently, it was apparent that Dr. Tom’s classroom would be the most effective use of my time. His method is clear, consistent, and most of all – it works.”

– Aldo Leon II, PE, Entergy Nuclear, New Orleans, Louisiana