Use the position function s(t) = -16t^2+1000, which gives the height (ft) of an object that has fallen for t seconds from a height of 1000 ft. The velocity at time t=a seconds is given by

lim s(a) - s(t) t->a a-t .

101. If a construction worker drops a wrench from a height of 1000 ft, how fast will the wrench be falling after 5 seconds?

102. If a construction worker drops a wrench from 1000 ft, when will the wrench hit the ground? At what velocity will the wrench impact the ground?