Welcome to PF!
The question isn't entirely clear to me - is it just an object dropping distance d from initial speed zero and final speed 10 ft/s?
If so, you need an accelerated motion formula relating Vf, a, and d. If you can't find one like that, you can use the two basic accelerated motion formulas for v and d to find the time and then the distance. Also, you must either convert everything to metric units and use a = 9.81 m/s² or else find the US value for the acceleration of gravity. Try putting that together and show us how far you get!