How Does a Pulley System Affect Scale Readings?

  • #1
orazon
4
1
Homework Statement
Impact of pulling a rope connected to a mass through a pulley on the weight reading of that person
Relevant Equations
Pulleys, Springs
A kid is standing on a scale and holding a rope that goes through a pulley, on the other side the rope is connected to a spring and then to a 50N mass item.
Assume that the kid's weight is 700N
1. While in static mode - what will the scale show?
2. The kid is now pulling the rope to get the mass higher from the floor - what will be the impact on the scale measurement?



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  • #3
1. While in static mode, I believe that the scale will show 650 N as the Tension on the rope will counter some of the gravity force
2. While pulling the rope, the scale will show an even lower weight as the Tension in the rope will increase (even though the mass is moving) so the counter-force on gravity will be even higher.
 
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  • #4
orazon said:
2. While pulling the rope, the scale will show an even lower weight as the Tension in the rope will increase (even though the mass is moving) so the counter-force on gravity will be even higher.
What would be an effect of the spring?
 
  • #5
Causing an increased tension on the rope?
 
  • #6
orazon said:
Causing an increased tension on the rope?
Does it make any difference that the mass is on the spring rather than attached to the rope directly?
 
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  • #7
The tension will still be the same, right?
 
  • #8
orazon said:
The tension will still be the same, right?
With the spring, the response will be dynamic.
 
  • #9
orazon said:
The tension will still be the same, right?
It would be good to try this out! Would the spring's response depend on how the rope was pulled? Could this get complicated?
 

FAQ: How Does a Pulley System Affect Scale Readings?

1. How does a pulley system change the force measured by a scale?

A pulley system can change the direction and magnitude of the force applied to a scale. Depending on the configuration, it can distribute the weight of the load across multiple strands of rope, effectively reducing the force measured by the scale. For example, in a simple pulley system with one movable pulley, the force on the scale is half the weight of the load.

2. Will a scale read the same weight if a pulley system is used?

No, a scale will not necessarily read the same weight if a pulley system is used. The reading depends on the mechanical advantage provided by the pulley system. A single fixed pulley changes only the direction of the force, so the scale reads the same weight. However, systems with movable pulleys or multiple pulleys can reduce the force the scale measures.

3. How does a movable pulley affect the reading on a scale?

A movable pulley effectively reduces the force needed to lift a load by distributing the weight across multiple segments of rope. This means that the scale will read a lower force compared to lifting the load directly. For instance, with one movable pulley, the scale would read half the weight of the load.

4. What happens to scale readings in a compound pulley system?

In a compound pulley system, which combines fixed and movable pulleys, the mechanical advantage increases, further reducing the force measured by the scale. The scale reading will depend on the total mechanical advantage. For example, a system with two movable pulleys can reduce the force to a quarter of the load's weight.

5. How do you calculate the scale reading in a pulley system?

To calculate the scale reading in a pulley system, you need to determine the mechanical advantage of the system. This is typically the ratio of the load's weight to the force exerted on the scale. For a system with n movable pulleys, the mechanical advantage is 2^n. The scale reading is then the load's weight divided by the mechanical advantage.

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