Optimizing String Placement for Accurate Friction Experiments

In summary: Theoretically, nothing. The string would be pulling the weights towards the ground at a rate much greater than the force it would take to push them away. So in this case, the scale would not register any force whatsoever. This is why the string needs to be parallel to the ground.Think about the extreme case. Suppose you allowed the string to form a very steep angle with the surface, say ninety degrees. Then what would the scale be measuring? Theoretically, nothing. The string would be pulling the weights towards the ground at a rate much greater than the force it would take to push them away. So in this case, the scale would not register any force whatsoever.
  • #1
kiddiegrade
11
0
Why does the string in an experiment setup fro friction experiment be parallel to the horizontal plane? What is its significance? (see picture attached)
 

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  • #2
First, and most important, the reading on the scale will be the amount of force required to pull the doowhat on the left hand side. You won't need trig to figure out force components and whatnot.
 
  • #3
But our teacher says that it is important that the string is parallel to the ground.. why?
 
  • #4
kiddiegrade said:
But our teacher says that it is important that the string is parallel to the ground.. why?

Because the experiment is attempting to measure the frictional force that is produced by a particular normal force.

If the string were angled up slightly as it goes toward the scale then it would be pulling up on the weights. They would be pressing down with less than their full weight on the ground since they would be partially supported by the string. The normal force would be reduced.

If the string were angled down slightly as it goes toward the scale then it would be pulling down on the weights. They would be pressing down with more than their full weight on the ground. The normal force would be increased.
 
  • #5
Because the experiment is attempting to measure the frictional force that is produced by a particular normal force.

If the string were angled up slightly as it goes toward the scale then it would be pulling up on the weights. They would be pressing down with less than their full weight on the ground since they would be partially supported by the string. The normal force would be reduced.

If the string were angled down slightly as it goes toward the scale then it would be pulling down on the weights. They would be pressing down with more than their full weight on the ground. The normal force would be increased.

I do not understand.. sorry.
 
  • #6
kiddiegrade said:
I do not understand.. sorry.

Think about the extreme case. Suppose you allowed the string to form a very steep angle with the surface, say ninety degrees. Then what would the scale be measuring?
 

1. What is the purpose of using string in an experiment setup?

The purpose of using string in an experiment setup is to create a controlled environment for the experiment. It is often used to suspend or hold objects in place, as well as to measure distance or tension.

2. What types of string are commonly used in experiments?

The most commonly used string in experiments include nylon, polyester, and cotton. These strings are strong, durable, and have minimal stretch, making them ideal for precise measurements and controlled conditions.

3. How do you ensure the accuracy of string measurements in an experiment?

To ensure accuracy, it is important to use a ruler or measuring tape to measure the length of the string. It is also crucial to keep the string taut and free from knots or kinks. Using the same type and thickness of string for each measurement can also help maintain consistency.

4. Can the type of string used affect the results of an experiment?

Yes, the type of string used can affect the results of an experiment. For example, a string with high elasticity may stretch under tension, leading to inaccurate measurements. It is important to choose a string that is appropriate for the specific experiment to ensure reliable results.

5. How should string be handled and stored in an experiment setup?

String should be handled with care to avoid tangling, knotting, or stretching. It is best to store string in a cool, dry place away from direct sunlight to prevent any changes in its properties. Additionally, storing string coiled or wound around a spool can help maintain its shape and prevent tangles.

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