What is the principle of an ideal machine ?

Explanation

### Step-by-Step Text Solution

1. **Definition of a Machine**: A machine is defined as a device that takes in energy (input) and converts it into work or energy output.

2. **Understanding Ideal Machines**: An ideal machine is one that operates with perfect efficiency. This means that it converts all the input energy into useful output energy without any losses.

3. **Efficiency of Ideal Machines**: The efficiency of an ideal machine is 100%. This implies that the work done by the machine (output work) is equal to the work done on the machine (input work).

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