Solving Crazy Salad Spinner's Puzzle: Find String Strength

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SUMMARY

The discussion centers on calculating the required strength of a replacement string for a salad spinner with a 6 cm radius wheel and a 12 cm basket radius. The user determined the torque exerted on the axle to be 0.23 Nm, based on the equation torque = I(angular acceleration). To ensure the string can withstand the operational forces, the user needs to calculate the tension in the string that corresponds to this torque, factoring in the weight of the wet spinach (0.1 kg) and the radius of the wheel.

PREREQUISITES
  • Understanding of torque and its calculation
  • Familiarity with angular acceleration concepts
  • Knowledge of tension in strings and forces
  • Basic physics principles related to rotational motion
NEXT STEPS
  • Calculate the tension in the string using the formula T = torque / radius
  • Explore the relationship between torque and angular acceleration in rotational dynamics
  • Investigate material properties of strings to determine suitable strength ratings
  • Review safety factors in mechanical design for dynamic loads
USEFUL FOR

Mechanical engineers, physics students, and anyone involved in designing or repairing mechanical systems that require an understanding of torque and material strength.

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Homework Statement


You grew up with a salad spinner that operates with a string attached to a wheel with a radius of 6 cm.
Unfortunately, the string broke last week and you need to get it working again before Thanksgiving. You
need to figure out how strong the replacement string must be in order to survive the holiday without
breaking. Under normal operations, it takes 0.2 sec for you to spin the salad from rest to 5 revolutions per
second. The basket of the spinner has a radius of 12 cm. You normally put 0.1 kg of wet spinach in the
spinner and you decide to make a conservative estimate, so you make calculations assuming that the
spinach is at the location that requires the most torque to get the spinner moving. What torque does the
string exert on the axle, and how strong a string do you need?


Homework Equations


torque = I(angular acceleration)


The Attempt at a Solution


I found the torque to be 0.23 Nm, but have absolutely no idea how to find the strength of the rope from there. Should I find tension?
 
Physics news on Phys.org
Yes. The string has to be capable of applying a force (=tension) via the 6cm radius wheel so that it produces the required torque.
 

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