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It is due to friction.
frictionIn real machines, as opposed to ideal machines, there is always friction that reduces the efficiency of the machine. Lubricants like oil can be used to reduce friction and improve efficiency.
Friction.
Because there is always going to be friction, the efficiency of any machine will always be less then 100 percent.
friction and other environmental forces ar responsible for <100 % efficiencies of machines.
The relationship between friction and the efficiency of a machine is when friction increases, efficiency decreases, and vice versa. That is why you can never have 100% efficiency, because there is always at least a little friction. They are inversely proportional, meaning, higher friction equals less efficiency.
Efficiency Efficiency
Efficiency of the machine is reduced due to loss of energy by friction.
The mass affects the efficiency of an object. It adds more weight, which causes more friction. More friction=less efficiency
Friction is the force that prevents all machines from being 100 percent efficient. It produces a resisting force that hinders the machine's complete functioning. Reducing friction will enhance efficiency.
That simply means that some energy is lost, due to friction and other causes.
If there is more friction with a machine, efficiency is less.