Question

Камень,брошенный горизонтально с высоты 2 м над землей,упал на расстоянии 7 м.найти начальную и конечную скорости мяча

Answer 1

Вот так будет понятней

Answer 2

Problem Analysis

We are given that a stone is thrown horizontally from a height of 2 meters above the ground and lands at a distance of 7 meters. We need to find the initial and final velocities of the stone.

Solution

To solve this problem, we can use the equations of motion. Since the stone is thrown horizontally, the initial vertical velocity is zero. We can use the equation:

h = (1/2)gt^2

where h is the height, g is the acceleration due to gravity, and t is the time of flight.

We can rearrange this equation to solve for t:

t = sqrt(2h/g)

Substituting the given values, we have:

t = sqrt(2 * 2 / 9.8) = sqrt(0.408) ≈ 0.639 seconds.

Since the stone is thrown horizontally, the horizontal velocity remains constant throughout the motion. We can use the equation:

d = vt

where d is the distance, v is the horizontal velocity, and t is the time of flight.

Substituting the given values, we have:

7 = v * 0.639

Solving for v, we get:

v ≈ 10.95 m/s.

Therefore, the initial and final velocities of the stone are approximately 10.95 m/s.

Conclusion

The initial and final velocities of the stone thrown horizontally from a height of 2 meters above the ground and landing at a distance of 7 meters are approximately 10.95 m/s.