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.
Drag force: 1/2*P*v2*A*Cd
x=vit + 1/2*at2
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=vit + 1/2*at2 and solve for a.
Then, using 1/2*P*v2*A*Cd = ma, i solve for Cd, 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?