The velocity is 4374.45 m/s.
I got the answer by using v=d/t.
20,000meters / 25min= 4,374.45 m/s.
Let us use the formula for Newton's Second Law of Motion:
Net force = Mass*Acceleration
Net force = Applied Force - μ*Normal Force
where μ is the coefficient of kinetic friction
Normal Force = Force due to gravity = mass*gravity
Normal Force = (210 kg)(9.81 m/s²) =<em> 2,060.1 N</em>
Then,
Net force = 4100 - 0.38*2060.1 = 3317.162 N
3317.162 N = (210 kg)(a)
Solving for acceleration,
<em>a = 15.796 m/s²</em>
Question
What is the length of the pipe?
Answer:
(a) 0.52m
(b) f2=640 Hz and f3=960 Hz
(c) 352.9 Hz
Explanation:
For an open pipe, the velocity is given by

Making L the subject then

Where f is the frequency, L is the length, n is harmonic number, v is velocity
Substituting 1 for n, 320 Hz for f and 331 m/s for v then

(b)
The next two harmonics is given by
f2=2fi
f3=3fi
f2=3*320=640 Hz
f3=3*320=960 Hz
Alternatively,
and 

(c)
When v=367 m/s then

Flux through each of the six faces of the cube: 
Explanation:
In this problem, a charge
is placed at the center of the cube.
We can apply Gauss Law, which states that the flux through the surface of the cube is equal to the charge contained within the cube divided by the vacuum permittivity; mathematically:

where
is the charge
is the vacuum permittivity
Here we want to find the flux through each of the six faces of the cube.
By simmetry, we can say that the 6 faces are identical: therefore, the flux through each of them must be the same. This means that the flux through each faces is 1/6 of the total flux through the total surface, therefore:

Learn more about electric fields:
brainly.com/question/8960054
brainly.com/question/4273177
#LearnwithBrainly