with what speed does a freely falling object dropped from a height of 88.2m hit the ground? how long does it take for it hit the ground?

Vf = 41.6 [m/s].

Explanation:

To solve this problem we must use the equations of kinematics.

Vf² = Vo² + (2*g*y)

where:

Vf =  final velocity [m/s]

Vo = initial velocity = 0

g = gravity acceleration = 9.81 [m/s²]

y = height = 88.2 [m]

Note: The positive sign of the equation tells us that the acceleration of gravity goes in the direction of motion.

Vf² = Vo² + (2*g*y)

Vf² = 0 + (2*9.81*88.2)

Vf = (1730.48)^0.5

Vf = 41.6 [m/s]

d.7.5cm is your answer