To solve this problem we will apply the linear motion kinematic equations.
The equation that describes the position as a function of the initial velocity, acceleration and time is given by the relation

Here,
Initial velocity
t = Time
a = Acceleration, at this case due to gravity
There is not initial velocity then we have that the equation to the given time is


If the ball is held at a height of 1m before it is dropped, we have that the Building height is


Answer:
a) 30.84m/s
b) 348.32Hz
c) 32.34m/s
d) 289.69Hz
Explanation:
a) If 1 mile=1609,34m, and 1 hour=3600 seconds, then 69mph=69*1609.34m/3600s=30.84m/s
b) Based on Doppler effect:
/*I will take as positive direction the vector
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c) 
d) 
The way that scientists ensure that data is reliable Clear Explanation