Determining the forces acting on a system

In summary, the force diagram shows three tension forces acting on the system. The first tension force is due to the friction between the person's hands and the rope, and the other two tension forces are located at the bottom pulley. These two tension forces are equal because the tension along a rope must be the same, according to Newton's third law. This is assuming the pulleys are frictionless.
  • #1
Mr Davis 97
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Homework Statement


Explain why the force diagram is as shown:

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[h2]Homework Equations[/h2][h2]The Attempt at a Solution[/h2]
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For the system, the gravity vector makes sense. However, I don not understand exactly why there are three tension forces. First of all, to me, it would seem that the first force is the force due to friction between the person's hands and the rope. I do not see what the force has to do with tension. Second of all, why are there two tension forces where the bottom pulley is? Shouldn't there only be one? How come there are two? I doon't really understand how tension works, so it is confusing me.
 

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  • #2
The hands versus the rope: think Newton's third law.

For the second question, consider that the tension along a rope must the the same (assuming the pulleys are frictionless), otherwise it would move
 

1. What is the purpose of determining the forces acting on a system?

The purpose of determining the forces acting on a system is to understand and predict the motion and behavior of that system. By analyzing the forces acting on the system, we can determine the net force and acceleration, and ultimately make predictions about the system's future state.

2. How do you calculate the net force acting on a system?

The net force acting on a system is calculated by adding together all of the individual forces acting on the system. If the net force is zero, the system will remain at rest or continue moving at a constant velocity. If the net force is not zero, the system will experience acceleration in the direction of the net force.

3. What are the different types of forces that can act on a system?

There are four main types of forces that can act on a system: gravitational, electromagnetic, strong nuclear, and weak nuclear. Gravitational forces are the attractive forces between any two objects with mass. Electromagnetic forces are the attractive or repulsive forces between charged particles. Strong nuclear forces hold atomic nuclei together, while weak nuclear forces are involved in radioactive decay.

4. How do you determine the direction of a force acting on a system?

The direction of a force acting on a system can be determined by its vector representation. A force vector has both magnitude (size) and direction. The direction of the force is indicated by the arrow on the vector, pointing in the direction in which the force is acting. The length of the arrow represents the magnitude of the force.

5. What are some real-life examples of determining forces acting on a system?

Determining forces acting on a system is important in many real-life situations. For example, when designing a bridge, engineers must consider the forces acting on the structure to ensure it can support the weight of traffic and withstand external forces such as wind. In sports, understanding the forces acting on a ball can help players make more accurate shots. In space exploration, scientists must consider the forces acting on spacecraft to navigate and land on other planets.

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