Single Fixed Pulley and Single Movable Pulley | Mechanical Advantage | Velocity Ratio | Efficiency

Summary

This video explains the principles of mechanical advantage using pulleys, illustrating the differences between single fixed and single movable pulleys. The instructor demonstrates how force can be applied more easily by pulling downward rather than upward. Key calculations are presented, showing that the mechanical advantage for both types of pulleys is 1 and 2, respectively, with efficiencies remaining at 100%. The video emphasizes the practical benefits of using pulleys in lifting heavy loads and encourages viewers to rewatch for clarity on the concepts discussed.

Takeaways

• 😀 A pulley is a simple machine used to lift or move loads by changing the direction of the applied force.
• 😀 There are two main types of pulleys: single fixed pulleys and single movable pulleys.
• 😀 In a single fixed pulley, the pulley is attached to a rigid support, making it easier to apply force downward.
• 😀 The mechanical advantage (MA) of a single fixed pulley is 1, meaning the load equals the effort applied.
• 😀 Efficiency of a single fixed pulley is 100%, as there is no loss of energy in the system.
• 😀 A single movable pulley allows for a reduction in the amount of effort needed to lift a load.
• 😀 In a single movable pulley, the load is supported by two tensions in the rope, giving it a mechanical advantage of 2.
• 😀 The velocity ratio (VR) of a single movable pulley is also 2, indicating that for every 2 meters of effort, the load moves 1 meter.
• 😀 By using a movable pulley, you can lift a heavier load with less effort (e.g., using 5 Newtons to lift 10 Newtons).
• 😀 Understanding the mechanics of pulleys, including their mechanical advantages and efficiencies, enhances their practical applications.

Q & A

What are the two ways to apply force when using a pulley?

The two ways to apply force when using a pulley are upward and downward. Applying force downward is generally easier.

What is a pulley, and how does it function in lifting loads?

A pulley is a simple machine that helps lift loads by changing the direction of the applied force. It allows a user to apply force in a downward direction, making it easier to lift a load.

How does a single fixed pulley differ from a single movable pulley?

A single fixed pulley is stationary and changes the direction of the force, while a single movable pulley can move up and down with the load, allowing for greater mechanical advantage.

What is mechanical advantage (MA), and how is it calculated?

Mechanical advantage is the ratio of the load lifted to the effort applied. It is calculated using the formula MA = Load / Effort.

What is the mechanical advantage of a single fixed pulley?

The mechanical advantage of a single fixed pulley is 1, meaning the load is equal to the effort applied.

What is the significance of the velocity ratio (VR) in pulley systems?

The velocity ratio indicates how much the effort distance differs from the load distance. It is calculated as VR = Displacement of Effort / Displacement of Load.

How is efficiency defined in the context of pulleys?

Efficiency is defined as the ratio of mechanical advantage to velocity ratio, expressed as a percentage using the formula Efficiency = (MA / VR) × 100.

What is the efficiency of both a single fixed pulley and a single movable pulley?

The efficiency of both a single fixed pulley and a single movable pulley is 100%.

What happens to the load when the effort is applied to a movable pulley?

In a movable pulley, when effort is applied, the load is supported by two tensions, allowing for a greater mechanical advantage, typically resulting in a load being twice the effort applied.

What is the relationship between the displacement of effort and the displacement of load in a movable pulley?

In a movable pulley, if the displacement of effort is 2 meters, the displacement of load will be 1 meter, indicating a halved load movement compared to effort movement.