Answer:The output work is always less than the input work because some of the input work is used to overcome friction. Therefore, efficiency is always less than 100 percent.
No machine is free from the effects of gravity, and even with wonderful lubrication, friction always exists. The energy a machine produces is always less than the energy put into it (energy input). ... That is why 100% efficiency in machines shall not be possible.
The hiker followed the north trail a distance of two kilometers in thirty minutes is an example that provides a complete scientific description of an object in motion.
