Question

С какой высоты падает мяч если он достигает земли со скоростью 20 м/с начальная скорость равна нулю

Answer 1

Дано:                       СИ
Vo = 0
V = 20 м/с
___________
H - ?

Решение:
Потенциальная энергия мяча в высшей точке:
Eп = m*g*H              (1)

Кинетическая энергия мяча в момент падения:
Eк = m*V²/2              (2)

По закону сохранения энергии приравняем (1) и (2)
 m*g*H = m*V²/2
2*g*H = V²
Н = V²/(2*g) = 20²/(2*10) = 400/20 = 20 м

Ответ:  H = 20 м

Answer 2

Calculating the Height from Which the Ball Falls

To calculate the height from which the ball falls, we can use the formula for gravitational potential energy:

Gravitational Potential Energy (GPE) = mass × gravity × height

The initial velocity of the ball is 0 m/s, and it reaches the ground with a velocity of 20 m/s. Using this information, we can calculate the height from which the ball falls.

We can use the following steps to calculate the height:

1. Calculate the change in potential energy using the formula: Change in GPE = GPE at the top - GPE at the bottom 2. Equate the change in GPE to the kinetic energy at the bottom to solve for the height.

Calculation Steps

1. Calculate the change in potential energy: - The change in GPE is given by the formula: ΔGPE = mgh - Since the initial velocity is 0, the initial kinetic energy is 0. - The final kinetic energy is given by: KE = 0.5mv^2 - The change in GPE is equal to the final kinetic energy.

2. Solve for the height: - Set the change in GPE equal to the final kinetic energy and solve for the height, h.

Calculation

The change in GPE is equal to the final kinetic energy: mgh = 0.5mv^2

Solving for h: h = (0.5v^2)/g

Where: - m = mass of the ball - g = acceleration due to gravity (approximately 9.81 m/s^2) - v = final velocity of the ball (20 m/s)

Result

Using the given values, the height from which the ball falls can be calculated using the formula: h = (0.5 * (20 m/s)^2) / 9.81 m/s^2

Conclusion

The height from which the ball falls can be calculated to be approximately 20.41 meters.