Question

С крыши дома высотой 20 меторов тело бросили вертикально вверх со скоростью 50 м/с.Через какое время тело упадёт на землю и с какой скоростью ?​

Answer 1

Тело упадёт на землю через 2,5с со скоростью 50м/с

Answer 2

Ответ:

10,4 с; 54 м/с

Объяснение:

Дано:

h₀ = 20м

v₀ = 50 м/с

_________

t, v - ?

Решение:

Рассмотрим движение тела вверх до точки наивысшего подъема:

v = v₀  - gt₁, v = 0 (в момент достижения максимальной высоты) ⇒ t₁ = v₀ / g

t₁ = 50 м/с / 10 м/с² = 5с

h = h₀ + v₀t₁ - gt₁²/2, h = 20 + 50*5 - 10*5²/2 = 145 (м)

Движение тела вниз (v₀ = 0)

h = gt₂²/2 ⇒ t₂ = √(2h/g), t₂ = √(2*145/10) = 5,4 (c)

t = t₁ + t₂, t = 5 + 5,4 = 10,4 (c)

v = gt, v = 5,4*10 = 54 (м/с)

Answer 3

Calculation of Time and Velocity

To calculate the time it takes for the object to fall from a height of 20 meters and the velocity at which it hits the ground, we can use the equations of motion.

The equation for the time it takes for an object to fall freely from a certain height is given by:

t = sqrt((2h)/g)

where: - t is the time in seconds, - h is the height in meters, and - g is the acceleration due to gravity, which is approximately 9.8 m/s^2 on Earth.

Using this equation, we can calculate the time it takes for the object to fall from a height of 20 meters:

t = sqrt((2 * 20) / 9.8) = sqrt(40 / 9.8) ≈ 2.02 seconds.

The equation for the final velocity of an object in free fall is given by:

v = sqrt(2gh)

where: - v is the final velocity in m/s.

Using this equation, we can calculate the velocity at which the object hits the ground:

v = sqrt(2 * 9.8 * 20) ≈ 19.8 m/s.

Therefore, the object will take approximately 2.02 seconds to fall to the ground, and it will hit the ground with a velocity of approximately 19.8 m/s.