# How to calculate drag caused by string?

An example - I throw a tennis ball with a short string hanging off one side. As the ball flies the string is dragged to the side opposite the direction of the ball's velocity vector, anchoring the ball and preventing rotation. How would I calculate the drag caused by the string?

I've found a formula for air resistance:

Resistance = ((air density * drag coefficient * area) / 2) * (velocity)$$^2$$

However I'm not sure if I'm able to simply take the ratio of the string's surface area to the surface area of the full object. I would think that the shape of the object and the straightness of the string would affect the result.

The end goal would be for me to be able to understand this concept in order to answer a hypothetical of how long an unbreakable string would have to be to allow a 14 m/s wind to be able to pick up a human, similar to a young spider leaving the egg.