The body is thrown vertically upward from the Earth at a speed of 20 m / s.

The body is thrown vertically upward from the Earth at a speed of 20 m / s. After what time and at what height will the body have a speed of 5 m / s?

Initial data: V (the speed with which the body was thrown vertically upwards) = 20 m / s; V1 (the speed that the body will reach) = 5 m / s.

Constants: g (acceleration due to gravity) = 10 m / s ^ 2 = -a.

1) Determine the time of movement: V1 = V + a * t = V – g * t.

t = (V1 – V) / (-g) = (5 – 20) / (-10) = 1.5 s.

2) Height that the body will reach: S = (V1 ^ 2 – V ^ 2) / 2a = (V1 ^ 2 – V ^ 2) / (2 * (-g)) = (5 ^ 2 – 20 ^ 2) / (2 * (-10)) = (25 – 200) / (-20) = 175/20 = 8.75 m.

Answer: The body will reach a height of 8.5 m in 1.5 s.