The oxidation number of nitrogen in n2 is

The oxidation number is equal to the charge on the ion.N2 is the divalent ion so the charge on N2 is zero as both the nitrogen atom share same number of electron and have same electronegativity. The dipole moment of N2 is zero.Therefore the cxidation number of N2 is 0.

Let's solve first for the impact speed. The impact speed or velocity of any free-falling body follows the formula written below:

v = √2gy
where
y is the height of the free fall

Now, the length of y includes the distance it took for the upward motion, and the free falling motion that covers the maximum height plus the remaining distance of 14.7 ft. Let's compute first the maximum height reached:

Hmax = v₀²/2g, where v₀ is the initial velocity
Hmax = (5.55 m/s)²/2(9.81 m/s²) = 1.57 m
Thus,
y = 1.57 m + 14.7 m = 16.27 m
v = √2(9.81 m/s²)(16.27 m)
v = 17.87 m/s

For the second question, there are two sections of the total time. The first is the time for the upward motion:
t₁ = 2v₀/g = 2(5.55 m/s)/(9.81 m/s²) = 1.13 s
The second section is the time for the free fall:
t₂ = √2y/g = √2(16.27 m)/9.81 m/s² = 1.82 s
Thus, the total time is:
Time = 1.13 s + 1.82 s = 2.95 s