Question

400 joules of work is done in raising a 72N weight
to a vertical distance of 5 meters with uniform
velocity. How much work is done against air
resistance as the weight is raised?
(1) 28 J
(2) 40 J
(3) 20 J
(4) 36 J​

Answer 1

Answer:

(2) 40J

Explanation:

Given that 400joule of work is done in raising a 72N weight to a vertical distance of 5 m .

So actual work done = f*s = 72×5 = 360J

Experienced work = 400j

so, work done against air resistance is = experienced work done - actual work done

400-360 = 40J answer

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