What is the work done on a slingshot?

AI Thread Summary
The discussion focuses on calculating the work done on a slingshot, emphasizing that work is not simply the product of force and distance due to the variable nature of the elastic force. The initial calculation yielded 0.0144J, but it was recognized as incorrect because the force changes as the slingshot stretches. The correct approach involves using the integral of force over distance rather than straightforward multiplication. This realization highlights the importance of understanding the principles of work in elastic systems. The conversation underscores the need to consider the non-constant nature of force when calculating work.
Goofball Randy
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Homework Statement



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Homework Equations



The given elastic force equation

The Attempt at a Solution



I plugged in the numbers, with 0.2m for the change in s and 45 for a. Since I knew that work was equal to force * distance, I multiplied that result by another 0.2m. This got me 0.0144J, or 14.4mJ. Since I knew that the slingshot was stretching in the direction you pull, the work had to be positive.

Unfortunately, my answer is incorrect. :(
 
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Don't forget that work is the INTEGRAL of F dot dL, not just straight multiplication!
 
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Goofball Randy said:

Homework Statement

The Attempt at a Solution



I plugged in the numbers, with 0.2m for the change in s and 45 for a. Since I knew that work was equal to force * distance, I multiplied that result by another 0.2m. This got me 0.0144J, or 14.4mJ. Since I knew that the slingshot was stretching in the direction you pull, the work had to be positive.

Unfortunately, my answer is incorrect. :(

The force is not constant, the work can not be calculated by multiplying maximal displacement with maximal force.
 
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Thanks guys! Seems really obvious now that I remember it.
 

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