Question

Why, in a real machine, is the output work always less than the input work?

Answer 1

The output work is always less than the input work because some input work is used to overcome friction. Therefore, efficiency is always less than 100 percent. All machines make work easier, but they don’t increase the amount of work that is done. Efficiency is the percent of work put into a machine by the user (input work) that becomes work done by the machine (output work). The output work is always less than the input work because some input work is used to overcome friction.