Question

(5) Work input
The work done on the machine by the effort,
is called work input (Winput), i.e.,​

Answer 1

Answer:

The solution to this problem is as follows,

A. In a simple machine, the input energy is not always equal to output energy as if it is moving there is friction between parts. If it is rotating it has to overcome air resistance. If it is a heat engine we can not extract all heat some is lost to the atmosphere. Hence A is False.

B. In Ideal machanical advantage we have,MA=FinFout

And ideally Fout≥Fin but in Actual machines the Fout<Fin, as friction and Air  resistance comes to play. Hence B is False.

C.Velocity ratio is defined as the ratio of displacement of effort to the displacement of the load. Hence C is correct.

D. The mechanical advantage of a single pulley is always less than 1 as Fout<Fin As some work is produced in overcoming the force of friction. Hence D is also False