Question

Тело бросили с высоты 9,8 м вертикально. Оно упало через 7,5 с. Ускорение принять 9,8 м/с². Определить направление и найти начальную скорость броска. Рисунок нужен с векторами. Не присылайте копии, пожалуйста.

Answer 1

Ответ: 35,44м/с

Объяснение:

Дано:

h=9,8м

t=7,5с

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Vo-?

Путь тела, брошенного вертикально с высоты, определяется по формуле:

h=Vo*t+gt²/2

Отсюда Vo*t=h-gt²/2 или

Vo=(h-gt²/2)/t=(9,8-(9,8*7,5²/2)/7,5=-35,44м/с

Знак (-) говорит о том, что тело бросили вертикально вверх с начальной скоростью 35,44м/с

Answer 2

Initial Analysis of the Situation

To solve this problem, we can use the equations of motion under constant acceleration. The body is thrown vertically from a height of 9.8 m and falls through a distance of 7.5 m with an acceleration of 9.8 m/s². We need to determine the direction and find the initial velocity of the throw.

Determining the Direction and Initial Velocity

To determine the direction and find the initial velocity of the throw, we can use the following equations of motion under constant acceleration:

1. Equation for Displacement: \( s = ut + \frac{1}{2}at^2 \) 2. Equation for Final Velocity: \( v = u + at \)

Where: - \( s \) = displacement - \( u \) = initial velocity - \( a \) = acceleration - \( t \) = time

Calculation Steps

1. Determining the Direction: Since the body is thrown vertically, the direction of the initial velocity will be either upward or downward. To determine this, we can use the displacement equation.

Using the equation \( s = ut + \frac{1}{2}at^2 \), we can solve for the initial velocity \( u \) using the given values of displacement \( s \), acceleration \( a \), and time \( t \).

Substituting the given values: - \( s = 9.8 \, \text{m} \) - \( a = 9.8 \, \text{m/s}^2 \) - \( t = ? \) (time is not given)

We need the time \( t \) to determine the direction.

2. Finding the Initial Velocity: Once we determine the direction, we can find the initial velocity using the equation for final velocity.

Using the equation \( v = u + at \), we can solve for the initial velocity \( u \) using the given values of final velocity \( v \), acceleration \( a \), and time \( t \).

Substituting the given values: - \( v = ? \) (final velocity is not given) - \( a = 9.8 \, \text{m/s}^2 \) - \( t = 7.5 \, \text{s} \)

Conclusion

To fully solve the problem and provide the direction and initial velocity of the throw, we need the value of time \( t \) or the final velocity \( v \). Once we have this additional information, we can proceed with the calculations to determine the direction and find the initial velocity of the throw.