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## Homework Statement

I made a wind tunnel for a science project and i am trying to determine its windspeed.

I decided to suspend a pingpong ball on a string in the wind tunnel and measure the angle change.

But to do this i need to calculate the drag force and i cannot do this without knowing the drag coefficient of the ball.

## Homework Equations

Drag force: 1/2*P*v

^{2}*A*C

_{d}

x=v

_{i}t + 1/2*at

^{2}

## The Attempt at a Solution

One idea i have is to drop the same ball from a height and measure the time it takes to hit the ground.

I then use the equation x=v

_{i}t + 1/2*at

^{2}and solve for a.

Then, using 1/2*P*v

^{2}*A*C

_{d}= ma, i solve for C

_{d}, and use this drag coefficient to solve for wind velocity in the wind tunnel.

However, i think i can't simply put ma= drag force becuase this suggests that gravity equals drag force which would mean the ball was at terminal velocity.

How would you solve this?