As long as the only force is the gravitational force, then the acceleration is the acceleration due to gravity, *g.* At Earthâ€™s surface the value is 9.8 m/s^{2}. (In the English system *g* = 32.2 ft/s^{2}.) If the object is dropped from rest at time *t* = 0, then the velocity at a future time *t* is simply *v* = gt. That is, the velocity increases by 9.8 m/s each second. If we measure the distance fallen from the position where it was dropped, then at time *t* it has fallen a distance *d* = 1/2 gt^{2}. The following table shows velocity and distance fallen for some selected times.