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Flying circus of physics


Monday, September 01, 2014


Jearl Walker
September 2014   In weight lifting, a deadlift requires that the weighted bar be lifted from the floor until the athlete’s legs and back are straight and then lowered back to the floor (not dropped). In March 2014, Lithuanian powerlifter Zydrunas Savickas set a new record with deadlift of 1155 pounds (corresponding to 524 kilograms and 5138 newtons) at the 2014 Arnold Strongman classic.

Instead of the conventional weight plates, he used wheels produced for Hummer vehicles.

Although that deadlift was stunning, the record for the greatest lift of any kind by anyone was reportedly set in 1957 by Paul Anderson. He employed a back lift in which he stooped beneath a reinforced wood platform that was supported by sturdy trestles. In front of him was a short stool against which he could both steady himself and push downward. On the platform were auto parts and a safe filled with lead. With an astonishing effort of both arms and legs, he lifted the platform by about a centimeter—the composite weight was 6270 pounds (2844 kilograms and 27 900 newtons)!

Comparisons of such powerful lifts is usually done in terms of force (pounds or newtons) or the corresponding mass (kilograms), but another way is to calculate the amount of work done in the lift. In physics, work done on an object is defined to be the product of the force applied to the object and the distance that the object is moved. The calculation does not include any of the other energy transfers that might be involved, especially when the force is produced by a person. For example, the thermal energy released in the muscles is not included.

Let’s approximate the lift distance for Savickas to be about 0.25 meter (because the bar sags, the weights are not lifted as far as the middle of the bar). Then the amount of work he did was

(5138 newtons)(0.25 meter) = 1280 newton-meter = 1280 joules.

Anderson, with the greatest lift in recorded history, surely exceed this work, but let’s check:

(27 900 newtons)(0.010 meter) = 280 joules.

Anderson certainly applied a far larger force, but work also depends on the distance an object is moved, and for him it was only a centimeter.

1016 pounds, deadlift Benedikt “Benni” Magnusson from Hanarfjordur, Iceland

documentary about Paul Anderson: part 2 part 3 part 4

Pub Tricks
If you would a list of the links to all the pub tricks I have posted, go here and then scroll down to "Pub physics".


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