Question

How long will it take an object to hit the ground if it is dropped from a hight of 176.4 meters ​

Answer 1

There's a short handy formula for that.

If the object is just dropped and not tossed, and it's not affected by air resistance on the way down, then the distance it falls in T seconds is

D = (1/2) (gravity) (T²)

For this problem . . .

176.4 m = (1/2) (9.8 m/s²) (T²)

Divide each side by  (4.9 m/s²) :

T² = (176.4 m) / (4.9 m/s²)

T² = (36 s²)

Take the square root of each side:

T = 6 seconds