The body was thrown vertically upward at a speed of V. In how many seconds will its speed decrease threefold?

Task data: V – body throw speed; V1 – considered speed (V1 = V / 3).

Constants: g – gravitational acceleration (g ≈ 10 m / s2).

The duration of body movement until the speed decreases by 3 times can be determined by the formula: t = (V1 – V) / a = (V – V1) / g.

Let’s calculate: t = (V – V / 3) / 10 = 2/3 V / 10 = 2V / 30 = V / 15.

Answer: For the speed of the thrown body to decrease 3 times, V / 15 time must pass.