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Furkat [3]
3 years ago
7

Power lifter Paul lifts a 700.0kg barbell 2.00m in 0.400s. How much power did Paul develop?

Physics
2 answers:
Vsevolod [243]3 years ago
6 0

         Work = (force) x (distance.

The force required to lift the load is its weight.

         Weight = (mass) x (gravity)

so    Work = (mass) x (gravity) x (distance)

Now  Power = (work) / (time)

so     Power  =  (mass) x (gravity) x (distance) / (time)

                      =  (700kg) x (9.8 m/s²) x (2 m)  /  (0.4 sec)

                      =  ( 700 x 9.8 x 2) / (0.4)  (kg-m²/sec²) / (sec)

                      =        ( 34,300 )                  (joule)  /  (sec)

                      =                     34,300 watts .

This is one of those exercises where the math and the physics
are air-tight and bullet-proof but the answer is absurd.

34,300 watts is about 46 horsepower.  I don't care how many
Wheaties Power Lifter Paul had for breakfast today, he is NOT
snatching a barbell that weighs  1,543 pounds (0.77 ton !)
to the height of the top of his head in less than 1/2 second !
yawa3891 [41]3 years ago
3 0
34,335 W 
P= mgh/t 
P=700*2*9.81/.4

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