What is the work done on a slingshot?

[Goofball Randy]

Homework Statement

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. :(

 

[Dishsoap]

Don't forget that work is the INTEGRAL of F dot dL, not just straight multiplication!

 

[ehild]

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.

 

[Goofball Randy]

Thanks guys! Seems really obvious now that I remember it.