Answer:
See below
Explanation:
Vertical position = 45 + 20 sin (30) t - 4.9 t^2
when it hits ground this = 0
0 = -4.9t^2 + 20 sin (30 ) t + 45
0 = -4.9t^2 + 10 t +45 = 0 solve for t =4.22 sec
max height is at t= - b/2a = 10/9.8 =1.02
use this value of 't' in the equation to calculate max height = 50.1 m
it has 4.22 - 1.02 to free fall = 3.2 seconds free fall
v = at = 9.81 * 3.2 = 31.39 m/s VERTICAL
it will <u>also</u> still have horizontal velocity = 20 cos 30 = 17.32 m/s
total velocity will be sqrt ( 31.39^2 + 17.32^2) = 35.85 m/s
Horizontal range = 20 cos 30 * t = 20 * cos 30 * 4.22 = 73.1 m
Answer : The volume of water in the pool is, 2473 ft³
Explanation :
First we have to calculate the average depth.
Given:
Diameter = 30 ft
Depth range : 1 to 6 ft linearly
average depth =
Now we have to calculate the volume of water in the pool.
Volume = area × average depth
V = π × (radius)² × 3.5
V = π × (30/2)² × 3.5
V = π × (15)² × 3.5
V = π × 225 × 3.5
V = 3.14 × 225 × 3.5
V = 2472.75 ft³ ≈ 2473 ft³
Therefore, the volume of water in the pool is, 2473 ft³
Answer:

Explanation:
Rydberg's formula is used to describe the wavelengths of the spectral lines of chemical elements similar to hydrogen, that is, with only one electron being affected by the effective nuclear charge. In this formula we can find the rydberg constant, knowing the wavelength emitted in the transcision between two energy states, we can have a value of the constant.

Where
it is the wavelength of the light emitted, R is the Rydberg constant, Z is the atomic number of the element and
are the states where
.
In this case we have Z=1 for hydrogen, solving for R:

This value is quite close to the theoretical value of the constant 
Answer:
1.11 m/s
Explanation:
The motion of the boat is an example of accelerated motion, since the velocity is not constant. However, we don't need to find the acceleration, because we are only interested in the average velocity of the boat, which is given by:

where d is the total distance covered and t the time taken. In this problem, the boat covered a distance of d = 20 m and it takes t = 18 s, therefore the average velocity is

Answer:
The velocity of the boy and the bicycle is 2.2 m/s.
Explanation:
We have,
Mass of child is 30 kg and the mass of bicycle is 20 kg. The combined momentum of the child and the bicycle is 110 kg-m/s.
It is required to find the velocity of the boy and the bicycle. The momentum of an object is given in terms of mass and its velocity. So,

M is combined mass of child and bicycle

So, the velocity of the boy and the bicycle is 2.2 m/s.