Answer:
The charge density in the system is 
Explanation:
To solve this problem it is necessary to keep in mind the concepts related to current and voltage through the density of electrons in a given area, considering their respective charge.
Our data given correspond to:
We need to asume here the number of free electrons in a copper conductor, at which is generally of 
The equation to find the current is
Where
I =Current
V=Velocity
A = Cross-Section Area
e= Charge for a electron
n= Number of free electrons
Then replacing,
Now to find the linear charge density, we know that
Where:
I: current intensity
Q: total electric charges
t: time in which electrical charges circulate through the conductor
And also that the velocity is given in proportion with length and time,
The charge density is defined as
Replacing our values
Therefore the charge density in the system is
Before swinging, T has only potential energy, (no speed)
Ui = mgh
Where h is the vertical displacement of T
From the laws of geometry,
cos45 = (L-h)/L
cos45 = 1-h/L
h/L = 1-cos45
h = L(1-cos45)
Therefore
Ui = mgL(1-cos45)
Proceeding the same way,
Twill raise to aheight of h' due to swing
h' = L(1-cos30)
The PE of T after swing is
Uf = mgh'
Uf = mgL(1-cos30)
Along with the PE , T has some kinetic energy results due to the moment.
Tf = 0.5*mv^2
According to the law of conservation of energy,
Ui = Uf+Tf
mgL(1-cos45) = mgL(1-cos30) + 0.5*mv^2
gL(co30-cos45) = 0.5*v^2
9.8*20*(co30-cos45) = 0.5*V^2
v = 7.89 m/s
<span>The speed f T after swing is 7.89 m/s</span>
Answer:
The height of the building is approximately 156.58 m
Explanation:
The mass of the ball dropped from rest from the building top = 0.660 kg
The time in which the ball falls, t = 5.65 seconds
The height, h, of the building is given from the following equation of motion;
h = u·t + ¹/₂·g·t²
Where;
u = The initial velocity of the ball = 0 m/s
g = The acceleration due to gravity = 9.81 m/s²
Plugging in the values, we have;
h = 0 × 5.65 + ¹/₂ × 9.81 × 5.65² ≈ 156.58 m
The height of the building, h ≈ 156.58 m.
