Rod Speed wrote:

"Robin" wrote in message
...
On 26/05/2017 12:35, Clive George wrote:
On 26/05/2017 08:55, Robin wrote:
There were more than one question however where there seemed to be
insufficient information.

The car skid for example.

Also the capstan.

The one with the weight hanging off rope at the top of the well? There's
enough information there.

I had in mind the nautical capstan with 4 men and "Which man would have to
work hardest to turn the capstan alone?" ISTM "hardest" is ambiguous
between (a) the force exerted (highest for shortest lever),

Yes, that's the obvious answer.

(b) the energy required per unit time (ditto if they walk at the same
speed - linear not angular - when walking alone),

That's not working harder.

and (c) the energy required per revolution (same for all).


If you assume the capstan has to be pushed with a constant rotational
speed then c) is right. If the man has a constant force available he
is doing more work the faster he walks so the furthest out one is the
answer. But unless the capstan has to be pushed at a constant speed it
is a bit hard to see any sensible answer for work done.



--

Roger Hayter