The body falls freely from a height of 40 m. What is its speed at the moment of impact on the ground? Find the time for the body to fall.

Body speed at the moment of falling:
S = (V² – V0²) / 2a, where S is the height of the body falling (S = 40 m), V is the final speed of the body (m / s), V0 is the initial speed of the body (for free fall V0 = 0 m / s) , а – acceleration of the body (а = g, g – acceleration of gravity (we take g = 10 m / s²)).
S = V² / 2g.
V = √ (2g * S) = √ (2 * 10 * 40) = √ (800) = 28.3 m / s.
Fall time:
S = V0 * t + a * t² / 2.
S = g * t² / 2.
t = √ (2S / g) = √ (2 * 40/10) = √ (8) = 2.83 s.