"Roger Hayter" wrote in message
...
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

They arent normally, so that cant be assumed and
that would have been stated if it was a requirement.

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.

a) is the obvious answer, because with the longer
arm, you have more leverage and so don’t have to
work so hard. That’s the whole point of the arms.