"The stall speed of a glider increases with the square root of the increase in weight. ... For example, a 540-pound glider has a stalling speed of 40 knots. The pilot adds 300 pounds of water ballast making the new weight 840 pounds. The new stalling speed is approximately 57 knots (square root of 300 + 40 = 57)."
- As some famous physicist said, it's "not even wrong".

Isn't not disclosing the right equation just as useless as the wrong equation?
https://www.quora.com/How-do-you-cal...of-an-aircraft