The engine that moves the cables for the San Francisco cable cars delivers 390.3 kW of power for each line. How long does it take for 6.5 ×10^6 J of work (about the amount of work needed to raise a partially loaded cable car up Nob Hill) to be done by this engine?

It would take 16.7 s for the work to be done by the engine.

Explanation:

From the question, given: Power = 390.3 kW

                                           Work to be done = 6.5 x J

But, power and work done with respect to time, has a relationship of:

Power =

So that,

time =

Thus,

time  =

       = 16.6539

time = 16.7 s

Time required is 16.7 seconds.

Thus, it would take 16.7 s for the work to be done by the engine.