Question

Камень брошен в горизонтальном направлении. Через 3 с после начала движения численное значение скорости камня стало в 5 раза больше его начальной скорости. Найти начальную скорость камня. Сопротивление воздуха не учитывать.

Answer 1

Дано V=5*Voх     t=3 с   Vo - ?

V= √Vу^2  +Vx^2
25*Vx^2=Vу^2+Vx^2
24*Vx^2=(g*t)^2
Vx=Vox=Vo=g*t/√24=30/√24=6 м/с

Answer 2

Problem Analysis

We are given that a stone is thrown horizontally and after 3 seconds, its velocity becomes 5 times its initial velocity. We need to find the initial velocity of the stone. The problem states that we should not consider air resistance.

Solution

Let's assume the initial velocity of the stone is v0.

According to the problem, after 3 seconds, the velocity of the stone becomes 5 times its initial velocity. Therefore, the velocity of the stone after 3 seconds is 5v0.

We can use the equation of motion for constant acceleration to solve this problem. Since the stone is thrown horizontally, the acceleration in the horizontal direction is zero.

The equation of motion for constant acceleration is:

v = u + at

where: - v is the final velocity - u is the initial velocity - a is the acceleration - t is the time

In this case, the final velocity (v) is 5 times the initial velocity (u), the acceleration (a) is 0, and the time (t) is 3 seconds.

Substituting these values into the equation, we get:

5v0 = v0 + 0 * 3

Simplifying the equation, we find:

5v0 = v0

Dividing both sides of the equation by v0, we get:

5 = 1

This is not a valid equation, which means there is an error in the problem statement or the given information. It is not possible for the final velocity to be equal to the initial velocity after a certain time if there is no acceleration.

Therefore, we cannot determine the initial velocity of the stone based on the given information.

Conclusion

Based on the given information, we cannot determine the initial velocity of the stone. There seems to be an error in the problem statement or the given information.