A movable pulley is used as:

Options

A. a force multiplier
B. a speed multiplier
C. a device to change the direction of effort
D. an energy multiplier

Answer

To solve the question regarding the function of a movable pulley, we can follow these steps:

### Step 1: Understand the Function of a Movable Pulley
A movable pulley is a type of pulley that can move up and down with the load. It is designed to make lifting easier.

**Hint:** Think about how pulleys work and what they are used for in lifting scenarios.

### Step 2: Determine the Mechanical Advantage
The mechanical advantage (MA) of a movable pulley is greater than 1. This means that the force needed to lift a load is less than the weight of the load itself.

**Hint:** Recall the formula for mechanical advantage, which is the ratio of load force to effort force.

### Step 3: Analyze the Force Required
With a movable pulley, you can lift a load by applying a force that is equal to half the load. This indicates that the pulley allows you to lift heavier loads with less effort.

**Hint:** Consider how much force you would need to apply to lift different weights with and without a movable pulley.

### Step 4: Identify the Role of the Movable Pulley
Since the movable pulley allows you to lift a load with less force, it acts as a force multiplier. This means it multiplies the input force, making it easier to lift heavy objects.

**Hint:** Think about the practical applications of pulleys in real life, such as cranes and elevators.

### Conclusion
A movable pulley is primarily used as a **force multiplier**.

**Final Answer:** The correct option is that a movable pulley is used as a force multiplier.