We use the equation of motion for vertical component,

Here,
is displacement of bullet,
is vertical initial velocity of bullet which is equal to zero because bullet was fired horizontally, and t is time of flight.
Therefore,

Given, 
Substituting the values, we get time of flight

Answer:

Explanation:
As we know that tension force in the string will be equal to the centripetal force on the string
so we will have

now we have

now we have


now when string length is 0.896 m and its speed is 71.5 m/s then we will have



Answer:
a. 0.18Hz
b. 0.56m/s
Explanation:
From the question we can deduct the following parameters
The wavelength, λ is define as the distance between two successful crest or trough and from the question we conclude that wavelength is 3.17m.
Also the period of the wave T can be computed as
T=22.6/4
T=5.65secs.
a. To compute the frequency, recall that frequency, F=1/period.
Hence,
F=1/5.65
F=0.18Hz
b. Next we compute the wave speed.
Wave speed=frequency *wavelength
Wave speed =0.18*3.17
Wave speed =0.56m/s