Determine the speed of the body in t = 3 s after it has been thrown horizontally at a speed of V0 = 39.2 M / s.

The body moves at a constant horizontal speed until it falls (Vg = 39.2 m / s). Vertical speed of the body: Vw = V0 + a * t (V0 is the initial vertical speed of the body (V0 = 0 m / s), a is the acceleration of the body (a = g, g is the acceleration of gravity (g = 10 m / s²), t – fall time (t = 3 s)).

Vv = g * t = 10 * 3 = 30 m / s.

Velocity vectors make an angle of 90º to each other, so we apply the Pythagorean theorem:

V² = Vg² + Vв².

V = sqrt (Vg² + Vb²) = sqrt (39.2² + 30²) = 49.36 m / s.