An escalator (moving stairs) and a lift (elevator) are both used to carry passengers from the same underground railway platform up to street level.
The escalator takes 20 seconds to carry a man to street level. The useful work done is W. The useful power developed is P. The lift takes 30 seconds to carry the same man to street level.
How much useful work is done by the lift, and how much useful power is developed by the lift?
1 )
useful work done by lift:more than W / useful power developed by lift:less than P
2 )
useful work done by lift:more than W / useful power developed by lift:P
useful work done by lift:W / useful power developed by lift:less than P
4 )
useful work done by lift:W / useful power developed by lift:P
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