Question 374316
We can determine the time it would take an object to fall (if there were no air resistance)
 by using the formula where d is the distance in feet and t is time in seconds.
:
A dropped object only has gravity effecting it which is 16t^2 = d
where
 t = the time in seconds
 d = distance it falls (in feet)
:
A. How long does it take a quarter dropped from the roof of a building 224 feet high to reach the ground?
16t^2 = 224
Divide both sides by 16
t^2 = +14
t = {{{sqrt(14)}}}
t = 3.74 seconds
:
B. If there are 5,280 feet in one mile, how long would it take an object to fall miles?
You neglected to say how many miles, assume it's 4 miles
Note d has to be in ft because the gravitational constant is in ft/sec
16t^2 = 4(5280) 
16t^2 = 21120
divide both sides by 16
t^2 = 1320
t = {{{sqrt(1320)}}}
t = 36.33 seconds
If it is not 4 miles, just use the same method using the given miles
:
C. If it takes an object 15.5 seconds to fall d feet, how tall is the object?
Write the equation as:
d = 16(15.5)^2
d = 16(240.25)
d = 3,844 ft