A type of single pulley is very often used as a machine even though it does not give any gain in mechanical advantage.
For what purpose is such a pulley used ?

Explanation

### Step-by-Step Solution:

1. **Understanding the Single Pulley**:
- A single pulley consists of a wheel on an axle or shaft designed to support movement and change the direction of force. It has a rope or cable that runs over the wheel.

2. **Mechanical Advantage of a Single Pulley**:
- The mechanical advantage (MA) is defined as the ratio of load (output force) to effort (input force). For a single pulley, the mechanical advantage is 1, meaning there is no gain in force; the effort applied is equal to the load lifted.

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