The maximum altitude that the bullet will reach is the point at which its velocity is zero. The equation that may be used in order to determine the altitude is,
                                  D = ((Vi)2 – (Vf)2)/2g
Where Vi and Vf are the initial and final velocities, respectively. g is the deceleration due to gravity.
Substituting the known values,
                                   D = ((700 m/s)2 – (0 m/s)2) / (2(-9.8 m/s2))
                                   D = 25000 m
Â
Thus, the maximum height is 25000 m.
Â
For the time needed to reach it, we use the equation,
                                   Vf = Vi – (g)(t)
Substituting,
                                   0 = 700 m/s – (-9.8 m/s2)(t)
The value of t is equal to 71.43 s.
Â
