Measuring Horsepower: The Dynamometer Quiz

AUTO

Olivia Seitz

6 Min Quiz

Image: shutterstock

About This Quiz

The dynamometer has undergone many adaptations and changes since its invention. Before it was used to measure how much "vroom" your vehicle has, what was its purpose? Test your knowledge of the dynamometer with this quiz!

What does a dynamometer measure?

The dynamometer measures the force-output of a machine. Force, torque, and power are all closely related quantities that it can quantify.

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From what language is the word "dynamometer" derived?

The word dynamometer is a combination of the words "dunamis," meaning power, and "metron," meaning measure. Hence, a dynamometer quite literally measures power!

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How are power and torque related?

Torque, or angular force, is multiplied by speed to get power. Most dynamometers measure the torque first, and the speed is determined separately to calculate power.

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What does a transmission dynamometer measure?

A transmission dynamometer is placed in between shafts of a device to measure torque at different points of the machine.

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How do absorption dynamometers measure torque?

Absorption dynamometers interrupt the source of power in such a way as to produce and measure the torque output. Some use fluid or mechanical friction, while others use electromagnetic induction.

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Which of the following are sub-classifications of absorption dynamometers?

The dynamometer experienced an explosion in uses and variants since the time of the Regnier dynamometer.

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What were the earliest dynamometers intended to measure?

While dynamometers were used extensively to test the strength of horses, the first known dynamometer was actually invented to test the strength of men!

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Who invented the first dynamometer?

The Graham-Desaguliers dynamometer is the earliest known dynamometer, appearing in London as early as 1763. Initially intended for human clinical measurements, it evolved into a wide spectrum of uses.

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Which group popularized the dynamometer in the late 1700s?

Because the dynamometer was able to measure human strength, it was used to determine who was stronger in a test of muscular feats.

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What problems did Regnier overcome in his updated design of the dynamometer?

The new and improved dynamometer was able to measure the strength of many different human limbs, from the beginning of life to its end. The design happened to solve the problem of measuring a horse's strength as well.

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What event interrupted Regnier's work on the dynamometer?

His work took place in a tumultuous time for France. Both of the men who commissioned the design - Buffon and Guéneau - perished during the French Revolution.

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What type of test did the Regnier dynamometer allow?

The beauty of Regnier's design was that the scales could be adjusted to accommodate either stretching or compressing the dynamometer.

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What component was critical to Regnier's design?

One of the most important components of Regnier's design was the metal spring, covered in leather. The brass plaque was added to protect the device during transport.

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How long was Regnier's dynamometer?

The entire contraption was only a foot long, making it easy to transport and use many times over.

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What was Regnier's trade, besides engineering?

Besides inventing the dynamometer, Regnier made a living by making and designing improvements for rifles.

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Francois Peron was the first person to record a study using the dynamometer. What did he study?

The ill-designed study concluded that the French and English were stronger than men from Australia, Timor, and Tasmania. The veracity of his findings was challenged on many grounds, in light of the exploitation of those peoples by Peron's peers.

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The next development in the history of the dynamometer came in the form of the Prony brake. When was it invented?

Gaspard de Prony invented the Prony brake in 1821, approximately three decades after Regnier's invention.

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What did the Prony brake do?

The Prony brake measured torque by stopping a wheel, to cause friction from the wheel to move a lever. The force needed to keep the lever from moving was measured on a scale, and the modern concept of a dynamometer was formed.

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When did Kelvin invent an upgrade to Prony's design?

Regnier's design, in addition to the Prony brake, inspired Kelvin to invent the "rope brake" dynamometer, capable of measuring engine power.

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Who invented the fan dynamometer?

The fan dynamometer relied upon wind resistance to function. Its accuracy was affected by changes in air pressure, humidity, and temperature, however.

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What did Kelvin's "rope brake" dynamometer look like?

The wheel (or drum) was attached to the engine that needed to be tested, and was cooled with water during the testing process.

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What is an eddy current dynamometer?

The eddy current dynamometer remains popular to this day. It measures engine output in terms of magnetic fields.

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What important process allows the eddy dynamometer to work?

We have Jean Foucault to thank for the existence of eddy dynamometers. He demonstrated the existence of eddy currents by placing copper in a magnetic field.

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Who invented the first hydraulic dynamometer in 1877?

Froude invented the hydraulic dynamometer at the behest of the British Admiralty. They wanted a way to measure the power of naval engines.

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Where was the horse pulling dynamometer rig invented?

A professor in Iowa wanted to set up an easy way to measure draft horse power in the 1920s. At the time, draft horses were the main way farmers plowed their fields, so they needed to know the horses were strong enough for the job.

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How much is one horsepower?

All of those answers are different ways of expressing one horsepower! A horsepower was approximately 150% of the work a mine pony could do on average in one minute.

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Who invented the term "horsepower?"

James Watt is the person who thought expressing power in terms of horses would be a good idea. He did all the calculations necessary to use it in everyday work. His name is also used to measure units of power, as in light bulbs.

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How much horsepower do today's cars have?

Cars have a surprising variety of horsepower ratings, depending on the build and purpose of the car. Luxury vehicles and sports cars trend at the higher end, at or under roughly 700 horsepower.

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How much horsepower can a space shuttle produce?

According to NASA, the three main engines for a space shuttle together produce about 37 million horsepower. You'd need an exceptional dynamometer to test that!

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What did James Watt use as the basis of a horsepower unit?

His idea was based on how much coal a mining pony could pull over a certain distance up from a coal mine in one minute.

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Where are engines usually tested with a dynamometer?

Depending on the vehicle, engines will be removed (or not) and hooked up to the dynamometer before testing. Once that's complete, the actual test only takes a few minutes.

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What important part of your car is calibrated with a dynamometer?

Vehicle spedometers are calibrated using dynamometers which measure speed and power outputs and compare them to a set of standard guidelines.

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What can affect a dynamometer reading?

Sports car enthusiasts who care about their engine's horsepower will often take into account weather conditions when getting final numbers for their vehicles.

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What does a chassis dynamometer look like?

A chassis dynamometer lets you drive your car onto a platform with large cylinders underneath. These are used to measure your car's horsepower, among other things.

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Which of the following is slang for dynamometer?

Most shops and manufacturers of dynamometers refer to them as "dynos," an easier to pronounce shortcut for the otherwise clumsy word, dynamometer. Dinosaurs come to mind, as well.

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