Positive drive means movement without slip such as the case in the linking between the crankshaft an the camshaft in the reciprocating engine. Negative drive, is an unusual term, allows slippage as with belt drive. Gears are said to be 'POSITIVE DRIVE" because there is no slippage between the input and output.

Positive Drive in Belt Drive:

A belt drive is a method of transferring rotational motion between two shafts using a flexible belt. It is a type of positive drive, which means that power is transmitted from the driving pulley to the driven pulley without any slip or loss of power. The positive drive ensures that the speed ratio between the two pulleys remains constant, resulting in an efficient power transmission system.

Explanation:

1. Positive Drive:
- In a positive drive system, the power is transferred from the driving element to the driven element without any slip or loss of power.
- It ensures that the speed ratio between the two elements remains constant, allowing for precise control of rotational speed and torque transmission.
- Positive drive systems are commonly used in applications where accuracy and efficiency are crucial, such as in industrial machinery and automotive systems.

2. Belt Drive:
- A belt drive is a mechanism that uses a flexible belt, typically made of rubber or synthetic materials, to transfer rotational motion between two parallel shafts.
- It consists of a driving pulley (also known as a sheave) connected to the driving shaft and a driven pulley connected to the driven shaft.
- The belt wraps around the pulleys, creating frictional forces that transmit power from the driving pulley to the driven pulley.
- Belt drives are widely used in various applications, including power transmission in machinery, automotive engines, and HVAC systems.

3. Advantages of Belt Drive:
- Belt drives offer several advantages, including smooth operation, low noise, and vibration damping.
- They are also relatively inexpensive, easy to install, and require minimal maintenance.
- Belt drives can accommodate large distances between shafts, allowing for flexibility in system design.
- They can transmit high power efficiently and can be used to achieve different speed ratios by using pulleys of different diameters.

Conclusion:

Among the given options, only the belt drive is a positive drive system. It ensures efficient power transmission without any slip or loss of power. The other options, such as chain drive, gear drive, and rope drive, may involve some degree of slip or power loss during operation.

Chain drive