A person in good physical condition can put out 100 W of useful power for several hours at a stretch, perhaps by pedaling a mechanism that drives an electric generator. Neglecting any problems of generator efficiency and practical considerations such as resting time: (a) How many people would it take to run a 4.00-kW electric clothes dryer?

40 persons

Step-by-step explanation:

Data provided:

The power put out by a single person = 100 W

Power required by an electric clothes dryer = 4.00 kW = 4000 W

Thus,

The number of persons required to produce 4000 W of power

= (Power required) / (power produced per person)

or

= (4000 W) / (100 W / person)

or

= 40 persons

Hence, the number of persons required is 40