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Question
A boy weighing 350 N climbs up 30 steps, each 20 cm high in 1 minute, Calculate:
- the work done and
- power spent.
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Solution
Force = weight of body = 350 N
Total distance = h = 30 × 20 = 600 cm
h = `600/100 = 6m`
(i) Work done W = F × h
W = 350 × 6 = 2100 J
(ii) Power spent = `"Work done"/"Time taken" = (30 × "Mg" × "h")/(1 " minute")`
= `((30 × 350 ×20)/100)/(1 " minute")`
= `(2100 J)/(1 " minute")`
= `(2100 J)/(60 " Sec")`
Power spent = 35
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