Question

1. In an ideal machine which of the following is true?

	a.	The work out of a machine is greater than the work into a machine, however, the force remains constant
	b.	The force into a machine will be different than the force out of a machine, however, the work in will be equal to the work out.
	c.	A machine changes both the force and the work (in and out)
	d.	A machine converts thermal energy into mechanical energy
	e.	An ideal machine is 50% efficient

Answer 1

(B)PART CORRECT OPTION.

Reason: (A) part cannot be correct, because if output work is greater than the input work, then the efficiency of the machine is more than 100% which is not possible.

For an ideal engine the output work is equal to the input work. This gives 100% efficiency for an ideal machine case. Remember in reality the 100% efficient machine is not possible. Because some part of the input work always get wasted in one or the other form.

Further,  the forces will be different but input work will be equal to the output work to give 100% efficiency for an ideal machine case.