Foam rubber ball hanging in a string - Forces

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SUMMARY

The discussion focuses on analyzing the forces acting on a foam rubber ball suspended by a string in front of a fan, which creates an airflow affecting the ball's position. The drag force is defined by the equation L = (8.7 × 10-4 Ns2/m2)v2, and the ball has a mass of 8.0 g. The ball is displaced at an angle of 38 degrees due to the airflow, and the participant seeks to determine the speed of the air impacting the ball. Key steps include drawing the forces and ensuring the mass is converted to kilograms for calculations.

PREREQUISITES
  • Understanding of Newton's laws of motion
  • Knowledge of vector addition in physics
  • Familiarity with drag force equations
  • Ability to convert mass units from grams to kilograms
NEXT STEPS
  • Calculate the speed of the air using the drag force equation
  • Explore vector resolution techniques for force diagrams
  • Study the principles of equilibrium in physics
  • Investigate the effects of different materials on drag force
USEFUL FOR

This discussion is beneficial for physics students, educators, and anyone interested in understanding the dynamics of forces acting on objects in fluid environments.

Norway
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Homework Statement


Okay, so I'm not originally an English speaker, so this may be silly reading for some of you, especially a lot of the words here, which isn't to find in the dictionaries either, but hopefully you'll at least get a picture of the task and help me solve it.

The drag (air resistance) of a ball made of foam rubber, is:
L = (8,7 \cdot 10^{-4} Ns^2 / m^2)v^2
The ball has a mass of 8,0 g.

We attach the ball to a piece of string hanging from the ceiling, and in front of a reversed vacuum cleaner. LOL. I have no idea what to call that machine in English, but it creates an air flow the affects the ball when it's hanging there in midair.

The air flow makes the ball move to the side, so that the string makes an angle of 38 degrees compared to straight down.

Draw an illustration showing the forces affecting the ball. Find the speed of the air when it passes the ball.


Homework Equations



I mentioned the only equation earlier, I think.

The Attempt at a Solution


No idea how to start. As for the drawing, I've written the gravitational force G straight down, the wind force V directly right and the string force parallel to the string, going from the ball. Is that correct? Anything else?

Thanks a lot.


Edit: I guess I could have called that "machine" a fan, and made it easy for myself. Lol.
 
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You have drawn the forces correctly. Now all you have to do is add them as vectors and say that their sum is zero. Don't forget to convert the mass from grams to kilograms.

** Edit **

A "reverse vacuum cleaner" is perfectly understandable.
 
Last edited:

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