Answer:
the initial velocity of the ball is 17.14 m/s
Explanation:
Given;
maximum height reached by the ball, h = 15 m
let the initial velocity of the ball = u
at maximum height, the final velocity of the ball is zero, v = 0
The initial velocity of the ball is calculated by using the following upward motion kinematic equation;
v² = u² - 2gh
0 = u² - 2(9.8 x 15)
u² = 294
u = √294
u = 17.14 m/s
Therefore, the initial velocity of the ball is 17.14 m/s
Answer:
With this information is not possible to calculate the mass.
Explanation:
This is a characteristic problem of energy conservation, where kinetic energy becomes potential energy. For this particular problem, we have the initial speed as input data. The moment the ball comes out of the cannon we have the maximum kinetic energy, as the ball goes up the ball will gain more potential energy as the ball loses kinetic energy, until the moment the ball reaches the maximum height. At the maximum height point, the ball will have its maximum potential energy while its kinetic energy is zero. In other words, all the kinetic energy that was, in the beginning, was transformed into potential energy.

In the above equation the masses are canceled and we can determine the maximum height, by means of the initial speed.
![h=\frac{0.5*v^2}{g} [m]](https://tex.z-dn.net/?f=h%3D%5Cfrac%7B0.5%2Av%5E2%7D%7Bg%7D%20%5Bm%5D)
But the mass cannot be determined, since it would be necessary to know the value of the energy, in order to determine the value of the mass.
The Balmer light series comes under the visible light.
<u>Explanation:</u>
The transition of electrons from higher to energy level with 2 as principal quantum number results in the spectral emission lines of hydrogen atom and this series of lines are known as Balmer series.
Mostly, these lines has the wavelength of more than 400 nm but lesser than 700 nm. Generally of the four categories namely, 410, 434, 486, 656 nm which comes under the type of visible light. So, it can be concluded that the Balmer series light falls under visible light.
In astronomy, Balmer lines occur in various stellar (celestial or astronomical) objects due to the higher content of hydrogen in the universe. Therefore, they are commonly seen and relatively strong when compared to other element lines.
Note: nm is nanometer (one billionth of a meter in length)