Question

Тело бросают вертикально вниз с поверхности земли со скоростью 20 м/с в яму. Через какое время тело будет на высоте 10 метров от дна ямы? Глубина ямы 30 м.

Answer 1

30м-10м=20м
То есть тело будет на высоте 10 м от дна ямы через 1 секунду, т.к. скорость падения тела равна 20 м/с
Ответ: через 1 секунду.

Answer 2

Problem Analysis

We are given that an object is thrown vertically downwards from the surface of the Earth into a pit with an initial velocity of 20 m/s. We need to determine the time it takes for the object to reach a height of 10 meters from the bottom of the pit. The depth of the pit is 30 meters.

Solution

To solve this problem, we can use the kinematic equation for vertical motion:

h = ut + (1/2)gt^2

Where: - h is the height from the bottom of the pit (10 meters) - u is the initial velocity (20 m/s) - g is the acceleration due to gravity (approximately 9.8 m/s^2) - t is the time

We can rearrange the equation to solve for time:

t = sqrt((2h)/g) - (u/g)

Let's substitute the given values into the equation and calculate the time.

Calculation

Using the given values: - h = 10 meters - u = 20 m/s - g = 9.8 m/s^2

Substituting these values into the equation:

t = sqrt((2 * 10) / 9.8) - (20 / 9.8)

Simplifying the equation:

t = sqrt(20 / 9.8) - (20 / 9.8)

Calculating the value:

t ≈ 1.02 seconds

Therefore, it will take approximately 1.02 seconds for the object to reach a height of 10 meters from the bottom of the pit.

Answer

The object will be at a height of 10 meters from the bottom of the pit after approximately 1.02 seconds.