Why is the work output of a machine always less than the work input?

Explanation

### Step-by-Step Solution:

1. **Understanding Work Input and Work Output**:
- Work input refers to the energy or work that is put into a machine to make it operate. This can be in the form of force applied over a distance.
- Work output is the useful work that the machine produces as a result of the work input.

2. **Identifying Friction in Machines**:
- In real-world scenarios, machines are not perfectly efficient. They have moving parts that create friction.
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