# How Does a Pulley with a Mechanical Advantage of 2 Affect Force?

• moomoocow
In summary, the mechanical advantage of a pulley with a mechanical advantage of 2 and a weight of 20N dangling below it means that in order to lift the weight, only 10N of force needs to be applied. However, if the weights are just hanging there, the pulley does not come into play and the force required to keep them suspended is still 20N.
moomoocow
Mechanical Advantage : Please Help!

hello

if there was a pulley, mechanical advantage of 2, and the force of the weights dangling below the pulley was 20N.
to find the 'upward' force, or force of the pulley
would it be 20N multiply by 2, due to mechanical advantage, making it 40N
or would it also be 20N?

can somebody please explain this simply?
thank you

That depends upon what you mean by "'upward' force, or force of the pulley'. "Mechanical advantage" depends upon the fact that there is a law of conservation of energy, not of force. If you were to lift a weight of 20 Newtons using this pulley, the "mechanical advantage" is 2 means that you would only have to apply 10 Newtons force- but you would have to pull on the rope twice as far as the weight is lifted in order to conserve energy. If the weights are just "dangling" there, no being lifted, the pulley doesn't come into play at all- there is no motion so no work done. The force downward on the weights is 20 N. Since they are not moving the force upward, due to the pulley must also be 20 N.

Hello,

Mechanical advantage is a measure of how much a machine can multiply the input force to produce a larger output force. In the case of a pulley with a mechanical advantage of 2, this means that for every 1 unit of input force, the pulley can produce 2 units of output force.

In your example, the force of the weights hanging below the pulley is the input force, which is 20N. So, according to the definition of mechanical advantage, the output force should be 2 times the input force, which is 40N. Therefore, the force of the pulley would be 40N.

I hope this helps to explain it simply. If you have any further questions, please let me know.

## 1. What is mechanical advantage?

Mechanical advantage is a measure of the amplification of force achieved by using a simple machine, such as a lever or pulley, to increase the output force of a system.

## 2. How is mechanical advantage calculated?

Mechanical advantage can be calculated by dividing the output force by the input force. This ratio represents the factor by which the force is amplified.

## 3. What is the difference between ideal and actual mechanical advantage?

Ideal mechanical advantage is the theoretical calculation of mechanical advantage based on the physical dimensions of a simple machine. Actual mechanical advantage takes into account friction and other real-world factors that may affect the output force.

## 4. How does mechanical advantage affect work and energy?

Mechanical advantage allows for the reduction of the amount of force needed to do work. This means that less work is required to achieve the same output force, resulting in a saving of energy.

## 5. What are some common examples of mechanical advantage in everyday life?

Examples of mechanical advantage can be found in many common tools and machines, such as scissors, wheelbarrows, and ramps. Even opening a door or using a bottle opener utilizes the concept of mechanical advantage.

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