# Solving Fictitious Forces w/ Massless Pulley

• yngstr
In summary, the direction of the fictitious force in a massless pulley system can be determined by considering the direction of motion of the object on each side of the pulley. The magnitude of the fictitious force can be calculated using Newton's second law, F=ma. The mass of the pulley can be ignored in these calculations, and there are many real-world applications for massless pulleys and fictitious forces. The number of pulleys in a system does not affect the calculation of fictitious forces.
yngstr

## Homework Statement

All surfaces are frictionless, pulley is massless. What force, F is needed so that m3 does not rise or fall?

Picture attached

F=ma

## The Attempt at a Solution

Found acceleration of system by dividing F by all three masses.

Found Fictitious force felt by m2 as a result of the acceleration.

Equated this fictitious force with m3g, isolated F.

Just wanted to know if this is the right method towards solving this problem, or am I missing something obvious/big?

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Though you haven't posted any equations, your logic is alright.

## 1. How do I determine the direction of the fictitious force in a massless pulley system?

The direction of the fictitious force in a massless pulley system can be determined by considering the direction of motion of the object on each side of the pulley. The fictitious force will always act in the opposite direction of the motion of the object.

## 2. How do I calculate the magnitude of the fictitious force in a massless pulley system?

The magnitude of the fictitious force in a massless pulley system can be calculated using Newton's second law, F=ma. Simply substitute the acceleration of the object on one side of the pulley into this equation to determine the magnitude of the fictitious force.

## 3. Can the mass of the pulley be ignored in calculations involving fictitious forces?

Yes, the mass of the pulley can be ignored in calculations involving fictitious forces. This is because a massless pulley does not contribute to the overall forces acting on the system, and therefore does not affect the acceleration of the objects.

## 4. Are there any real-world applications of massless pulleys and fictitious forces?

Yes, massless pulleys and fictitious forces have many real-world applications, particularly in mechanical systems. For example, they are commonly used in elevators, cranes, and other systems that involve the use of pulleys to lift heavy objects.

## 5. How does the number of pulleys in a system affect the calculation of fictitious forces?

The number of pulleys in a system does not affect the calculation of fictitious forces. As long as the pulleys are considered to be massless, the calculation of fictitious forces will remain the same regardless of the number of pulleys in the system.

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