Question

Мальчик бросил горизонтально мяч из окна ,находящегося на высоте 20м.Сколько времени летел мяч до земли и с какой скоростью он был брошен ,если он упал на расмтоянии 6 м от основания дома?

Answer 1

h=20   S=6
h=gt²/2     ⇒  t=√(2h*g)=4 c

v=S/t=6/4=1.5 м/с

Answer 2

Calculation of Time and Speed

To calculate the time it took for the ball to fall to the ground and the initial speed at which it was thrown, we can use the equations of motion and the given information.

The height from which the ball was thrown is 20 meters, and it fell at a distance of 6 meters from the base of the house.

Using the equation h = ut + (1/2)gt^2, where: - h is the height (20 meters), - u is the initial velocity (unknown), - t is the time (unknown), and - g is the acceleration due to gravity (approximately 9.8 m/s^2),

we can solve for t:

20 = ut + (1/2)(9.8)t^2 Next, we can use the equation s = ut, where: - s is the distance (6 meters), - u is the initial velocity (unknown), and - t is the time (unknown),

to solve for u:

6 = ut Now, let's solve these equations to find the time and initial velocity.

Solving for Time

From the equation 20 = ut + (1/2)(9.8)t^2, we can rearrange it to get a quadratic equation:

(1/2)(9.8)t^2 + ut - 20 = 0

Simplifying the equation, we get:

4.9t^2 + ut - 20 = 0

To solve this quadratic equation, we can use the quadratic formula:

t = (-u ± √(u^2 + 4(4.9)(20))) / (2(4.9))

Since we are interested in the positive value of t (time cannot be negative), we can ignore the negative solution.

Solving for Initial Velocity

From the equation 6 = ut, we can rearrange it to solve for u:

u = 6 / t

Now, let's substitute the value of t into this equation to find the initial velocity.

Calculation Results

To calculate the time and initial velocity, we need the value of t. Unfortunately, the exact value of t cannot be determined without additional information. The given information does not provide any details about the angle at which the ball was thrown or any other relevant factors.

Therefore, without additional information, we cannot calculate the exact time and initial velocity of the ball.