Question

Камінь кинутий вертикально зі швидкістю 10 м/с. На якій висоті його швидкість зменшиться вдвічі? Срочно, но не копируйте с другого ответа. там плохо

Answer 1

Дано: Vo=10 м/с; V=5 м/с; h - ?

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h=(V²-Vo²)/(-2g)

h=(5²-10²)/(-20)=3,75 м  -  это ответ.

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ИЛИ

По закону сохранения механической энергии:

Екин1=Екин2+Епот

mV²/2=m(V/2)²/2 + mgh

10²/2=5²/2 + 10h

10h=100/2 - 25/2

10h=75/2

h=75/20

h=3,75 м  -  это ответ.

Answer 2

Problem Analysis

To determine the height at which the velocity of a stone thrown vertically with an initial velocity of 10 m/s will decrease by half, we can use the equations of motion for uniformly accelerated motion. The stone is thrown vertically, so the only acceleration acting on it is due to gravity. We can use the equation:

v^2 = u^2 + 2as

where: - v is the final velocity - u is the initial velocity - a is the acceleration (in this case, due to gravity) - s is the displacement

We know the initial velocity (u) is 10 m/s and we want to find the height (s) at which the velocity decreases by half. Let's denote the final velocity as v/2. We can rearrange the equation to solve for s:

s = (v^2 - u^2) / (2a)

Calculation

Let's calculate the height at which the velocity of the stone will decrease by half.

Given: - Initial velocity (u) = 10 m/s - Final velocity (v/2) = 5 m/s - Acceleration due to gravity (a) = 9.8 m/s^2 (approximate value on Earth)

Using the equation above, we can substitute the values and calculate the height (s):

s = ((v/2)^2 - u^2) / (2a)

s = ((5)^2 - 10^2) / (2 * 9.8)

s = (25 - 100) / 19.6

s = -75 / 19.6

s ≈ -3.82 meters

The negative sign indicates that the stone is below the reference point (the point from which it was thrown). However, in this context, it doesn't make sense to have a negative height. Therefore, we can conclude that the velocity of the stone will never decrease by half when thrown vertically with an initial velocity of 10 m/s.

Conclusion

The velocity of the stone will not decrease by half at any height when thrown vertically with an initial velocity of 10 m/s.