Question

3 підвищення висотою 30 м кидають тіло в горизонтальному напрямі з швидкістю 72 км/год. Визначити через який час та з якою швидкістю в на поверхню бiля пiднiжжя?​

Answer 1

Ответ: 31,6м/с

Объяснение:

Дано:

h=30м

g=10м/с²

Vо=72км/ч=20м/с

------------------

t-?; V-?

Время, через которое тело упадет на землю, находим по  формуле:

t=√(2h/g), где:

h-высота, с которой падает тело;

g-ускорение свободного падения.

t=√(2*30/10)=2,4с

Вертикальная скорость, с которой тело упадет на землю, равна:

Vy=√(2gh)=√(2*10*30)=24,5м/с

Общая скорость, с которой тело упадет на землю, находим по теореме Пифагора:

V=√(Vo²+Vy²)=√(24,5²+20²)=31,6м/с

Answer 2

To determine the time and speed at which the body reaches the surface near the foot of a 30 m high object when thrown horizontally with a speed of 72 km/h, we can use the equations of motion.

Let's break down the problem step by step:

Given:

- Initial height (h) = 30 m - Initial horizontal velocity (u) = 72 km/h

Step 1: Convert the units

First, let's convert the initial horizontal velocity from km/h to m/s. We know that 1 km/h is equal to 0.2778 m/s. So, the initial horizontal velocity (u) is: - u = 72 km/h * 0.2778 m/s/km/h = 20 m/s

Step 2: Calculate the time of flight

Since the body is thrown horizontally, the vertical component of its velocity is zero. We can use the equation for vertical displacement to find the time of flight (t): - h = (1/2) * g * t^2, where g is the acceleration due to gravity (approximately 9.8 m/s^2) - Rearranging the equation, we get: t = sqrt(2h/g)

Substituting the given values, we have: - t = sqrt(2 * 30 m / 9.8 m/s^2) = sqrt(6.12 s^2) ≈ 2.47 s

Therefore, the time of flight is approximately 2.47 seconds.

Step 3: Calculate the horizontal distance traveled

To find the horizontal distance traveled by the body, we can use the equation for horizontal displacement: - d = u * t, where d is the horizontal distance traveled

Substituting the values, we have: - d = 20 m/s * 2.47 s ≈ 49.4 m

Therefore, the body will reach the surface near the foot of the object after approximately 2.47 seconds and at a horizontal distance of approximately 49.4 meters.

Please note that this calculation assumes no air resistance and a constant acceleration due to gravity.