Agrapefruit falls from a tree and hits the ground 0.89 s later. how far did the grapefruit drop? what was its speed when it hit the ground?

1) The free fall motion of the grapefruit is an uniformly accelerated motion, with constant acceleration equal to , therefore the distance covered by the grapefruit in a time t is equal to

Substituting , we get how far the grapefruit dropped:


2) The speed at time t in an uniformly accelerated motion of free fall is given by

where is the initial speed, that in this case was zero. Therefore, using t=0.89 s we can find the speed just before the grapefruit hits the ground:

Work is reduced while time is decreased