A crane lifts a load 500kg through a vertical distance of 4m in 8 seconds. Determine:

A crane lifts a load 500kg through a vertical distance of 4m in 8 seconds. Determine:
(i) Work done by the crane
(ii) Power developed by the crane
(iii) Efficiency of the crane given that it is operated by an electric motor rated 2.8Kw

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(i) Work done = P.E gained ;
= mgh
= 500 x 4 x 10;
= 20,000J;

(ii) Power = work done
time taken
= 20,000/8
= 2.5KW ; or (2500 watts);

(iii) Efficiency = work output x100;
work input
= 2.5/2.8 x 100;
= 89.29%;

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sharon kalunda answered the question on April 2, 2019 at 09:00

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