Question

Мяч уронили с высоты 20 м. Какую скорость будет у мяча у поверхности земли?

Answer 1

Ответ:Ответ 20 м/с

mgh=mV2/2

gh=V2/2

V2=2gh

V2=2×10н/кг×20м

V2=400

V=20 м/с

Объяснение:

Answer 2

To calculate the speed of the ball when it hits the ground, we can use the principles of physics, specifically the equations of motion under constant acceleration due to gravity.

When the ball is dropped from a height of 20 meters, it undergoes free fall, and the only force acting on it is gravity. The acceleration due to gravity near the surface of the Earth is approximately 9.81 meters per second squared (m/s^2) downward.

To find the final velocity (v) of the ball just before it hits the ground, we can use the following kinematic equation:

v^2 = u^2 + 2as

where: v = final velocity (unknown, to be determined) u = initial velocity (which is 0 m/s as the ball is dropped, so u = 0) a = acceleration due to gravity (approximately -9.81 m/s^2, negative because it acts downward) s = displacement (height from which the ball was dropped, which is 20 m)

Now, let's plug in the values:

v^2 = 0 + 2 * (-9.81) * 20 v^2 = -392.4

Taking the square root of both sides to find v:

v = √(-392.4)

Since velocity can't be negative in this context (it just indicates the direction), the ball's speed just before hitting the ground will be approximately:

v ≈ 19.8 m/s

So the speed of the ball just before it hits the ground will be about 19.8 meters per second.