Question

Кирпич упал с некоторой высоты с нулевой начальной скоростью и при ударе о землю имел скорость 40 м/с.Чему равно время падения? С какой высоты падал кирпич?Сопротивлением воздуха принебречь

Answer 1

Комментприй к вопросу- это мой ответ , перепутал кнопки. ;D

Answer 2

Calculation of Time of Fall and Height of Brick

To calculate the time of fall and the height from which the brick fell, we can use the equations of motion. Given that the brick fell from a certain height with zero initial velocity and had a velocity of 40 m/s upon impact with the ground, we can assume that the only force acting on the brick is gravity, and we can neglect air resistance.

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

v = u + gt

where: - v is the final velocity (40 m/s) - u is the initial velocity (0 m/s) - g is the acceleration due to gravity (approximately 9.8 m/s^2) - t is the time of fall (unknown)

Rearranging the equation, we can solve for t:

t = (v - u) / g

Substituting the given values, we have:

t = (40 m/s - 0 m/s) / 9.8 m/s^2

Calculating this, we find:

t ≈ 4.08 seconds.

To calculate the height from which the brick fell, we can use the equation for displacement:

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

where: - s is the displacement (unknown) - u is the initial velocity (0 m/s) - g is the acceleration due to gravity (approximately 9.8 m/s^2) - t is the time of fall (4.08 seconds)

Since the brick was dropped from rest, the initial velocity u is zero. Rearranging the equation, we can solve for s:

s = (1/2)gt^2

Substituting the given values, we have:

s = (1/2) * 9.8 m/s^2 * (4.08 s)^2

Calculating this, we find:

s ≈ 83.78 meters.

Therefore, the time of fall is approximately 4.08 seconds, and the height from which the brick fell is approximately 83.78 meters.