The body is thrown vertically upward at a speed of 20 m / s. At what height and after

The body is thrown vertically upward at a speed of 20 m / s. At what height and after how long will the body’s speed be half the initial speed?

The acceleration formula when moving vertically upward looks like:

g = (V – V0) / t, where

V, V0 – final and initial velocities of body movement,

t is the time during which the speed changes.

Hence V – V0 = g * t;

g = -9.8 as the body is moving up.

10 – 20 = -9.8 * t;

t = 10 / 9.8;

t = 1.02 s.

The height will be equal to the path. We find it by the formula: S = V0 – g * t ^ 2/2.

S = 20 – 9.8 * 1.02 ^ 2/2 = 20 – 10.2 / 2 = 20 – 5.1 = 14.9 m.

Answer: The body speed will be 2 times less at a height of 14.9 m in 1.02 s.