Question

Тело брошено вертикально вверх с начальной скоростью 40 м/с. Через сколько секунд полёта его скорость уменьшится в 10 раз? Ускорение свободного падения принять 10 м/с2. В ответе записать только число, без единиц измерения

Answer 1

Дано:

h = 10 м

v0 = 20 м /с

g = 10 м/с2

Найти:

v

Решение:

движение равноускоренное

h = (v^2 – v0^2) / 2g

v = √ (v0^2+ 2gh)

v = √ (20^2+ 2*10*10) = 24,5 м/с

Ответ: V = 24,5 м/с

Answer 2

Problem Analysis

We are given the initial velocity of an object thrown vertically upwards, and we need to determine the time it takes for its velocity to decrease by a factor of 10. The acceleration due to gravity is given as 10 m/s^2.

Solution

To solve this problem, we can use the equations of motion for uniformly accelerated linear motion. The equation that relates the final velocity (vf), initial velocity (vi), acceleration (a), and time (t) is:

vf = vi + at In this case, the initial velocity (vi) is 40 m/s, and the acceleration (a) is -10 m/s^2 (negative because the object is moving against the direction of gravity). We need to find the time (t) when the final velocity (vf) is 1/10th of the initial velocity (vi).

Let's substitute the given values into equation and solve for time (t):

vf = vi + at

vf = (1/10) * vi

(1/10) * vi = vi + (-10) * t

Simplifying the equation:

1/10 = 1 - 10t

10t = 1 - 1/10

10t = 9/10

t = (9/10) / 10

t = 9/100

Therefore, the time it takes for the velocity of the object to decrease by a factor of 10 is 9/100 seconds.

Answer

The velocity of the object will decrease by a factor of 10 after approximately 9/100 seconds.