# Does Weight Difference Affect Velocity in a Frictionless Pulley System?

• bobie
In summary, if two weights of equal mass are hung on a frictionless pulley, they will remain at rest. However, if one weight is slightly heavier, it will cause the other weight to fall and the final velocity will be infinite. To determine the final velocity, one can use free body diagrams or energy conservation equations.
bobie
Gold Member
If two weights (Edit: hanging 10m above ground) on a frictionless pulley are equal (10kg) they will rest. If one is even slightly heavier (10.1kg) it will start to fall lifting up the other.

Is final velocity dependent on the difference of weight, or it will the same as if there is no counterweight?

Last edited:
What do you think?

The final velocity is infinite, the acceleration rate of the system is the dependent, the root equation :
f = m * a

bobie said:
Is final velocity dependent on the difference of weight, or it will the same as if there is no counterweight?
Are you familiar with free body diagrams? If so, then draw one for each weight, use that to help you write two equations in two unknowns. Then solve.

dean barry said:
The final velocity is infinite
I assume that "final" is when the counterweight hits the pulley.

DaleSpam said:
Are you familiar with free body diagrams? If so, then draw one for each weight, use that to help you write two equations in two unknowns. Then solve.
Or use energy conservation to see if the velocity is the same.

A.T. said:
Or use energy conservation to see if the velocity is the same.
Excellent suggestion, that is even easier than my approach.

1 person

## 1. What is weight and counterweight?

Weight and counterweight refer to a system in which two objects balance each other out by exerting an equal and opposite force on each other. This is based on the principle of Newton's third law of motion, which states that for every action, there is an equal and opposite reaction.

## 2. How does weight and counterweight work?

In a weight and counterweight system, the heavier object exerts a greater force on the lighter object, causing it to move in the opposite direction. This creates a balance between the two objects, allowing them to remain in a stable position.

## 3. What are some examples of weight and counterweight systems?

One common example is a see-saw, in which the weight of one person on each end balances out the weight of the other. Another example is a balance scale, where weights are added to one side to balance out the weight of an object on the other side.

## 4. How is weight and counterweight used in everyday life?

Weight and counterweight systems are used in a variety of everyday objects, such as elevators, cranes, and even window blinds. They allow for the efficient movement of heavy objects and help to maintain balance and stability in various structures and machines.

## 5. What are the advantages of using weight and counterweight systems?

One major advantage is that weight and counterweight systems provide a stable and balanced structure, which reduces the risk of accidents or malfunctions. They also allow for the efficient use of energy, as the force exerted by the objects balances out instead of requiring additional force to keep them in place.

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