The stone falls freely without initial speed. How long will it take it to fly the third meter of its path?

V0 = 0 m / s.

g = 10 m / s2.

S3 = 3 m.

S2 = 2 m.

t -?

To find the time of passage of the third meter when moving t from the time of passage of three meters t3, it is necessary to subtract the time of passage of two meters t2: t = t3 – t2.

The stone moves uniformly with the acceleration of gravity g. The path of its movement is expressed by the formula: S = V0 * t + g * t ^ 2 / 2. Since it fell, it means V0 = 0 m / s and the formula will take the form: S = g * t ^ 2/2.

S2 = g * t2 ^ 2/2.

t2 = √ (2 * S ^ 2 / g).

t2 = √ (2 * 2 m / 10 m / s2) = 0.63 s.

S3 = g * t3 ^ 2/2.

t3 = √ (2 * S3 / g).

t3 = √ (2 * 3 m / 10 m / s2) = 0.77 s.

t = 0.77 s – 0.63 = 0.14 s.

Answer: the stone will fly the third meter of its path in time t = 0.14 s.