From what height did the body fall if it was in flight for 2 seconds?

Neglecting the air resistance, we find that the vertical movement of the body is uniformly accelerated, with the acceleration of gravity g = 9.8 m / s2.

The equation of body movement along the vertical:

H = V0 t + g t ^ 2/2,

where H is the initial body height above ground level, m; V0 is the initial vertical velocity of the body; by the condition of the problem, V0 = 0; t is the time of the body falling, s.

Substitute the values of the quantities:

H = g t ^ 2/2 = 9.8 × 2 ^ 2/2 = 19.6 m.

Answer: H = 19.6 m.