The ball was thrown vertically upward at a speed of 20 m / s. How long does it take

The ball was thrown vertically upward at a speed of 20 m / s. How long does it take for the ball to cover the distance of 30 m?

Given:

v0 = 20 m / s – initial speed of the ball thrown vertically upwards;

g = 10 m / s2 – free fall acceleration;

S = 30 meters.

It is required to determine the time t (seconds) during which the ball will cover the path S.

Let’s find the time it takes for the ball to rise to the maximum height:

t1 = v0 / g = 20/10 = 2 seconds.

The maximum height will be:

H = v0 * t – g * t ^ 2/2 = 20 * 2 – 10 * 22/2 = 40 – 20 = 20 meters.

It turns out that the ball will overcome 20 meters in 2 seconds, and then it will start falling down without an initial speed. The remaining S2 = 10 meters the ball will overcome in the following time:

t2 = (2 * S2 / g) ^ 0.5 = (2 * 10/10) ^ 0.5 = 20.5 = 1.4 seconds.

The total time will be equal to:

t = t1 + t2 = 2 + 1.4 = 3.4 seconds.

Answer: the ball will cover the distance of 30 meters in 3.4 seconds.