Answer:
Kinetic energy depends on the velocity of the object squared. This means that when the velocity of an object doubles, its kinetic energy quadruples.
To develop the problem it is necessary to apply the equations related to the moment of inertia.
The given values can be defined as,




According to the definition of the moment of inertia applied to the exercise we can arrive at the equation that,

Where n is the number of spokes necessary to construct the wheel.


Replacing the values at the general equation we have,

Solving for n,

Therefore the number of spokes necessary to construct the wheel is 36
PART B) The mass of the wheel is given by the sum of all masses and the total spokes, then



Therefore the mass of the wheel must be of 1.36Kg
By definition we have to:
The electric current is the flow of electric charge due to the movement (usually of electrons) that a material travels.
Some properties are:
1) Electric conduction: The conductive materials have a large amount of free electrons, therefore, the passage of electricity is possible.
2) The current inside a circuit is directly proportional to the voltage and inversely proportional to the resistance of the circuit. This is what is known as ohm's law:

3) The current can be continuous or alternate.
Alternating current is the electric current in which the magnitude and direction vary cyclically.
The direct current is the flow of electric charges that does not change direction with time.
Answer:
U₂ = 20 J
KE₂ = 40 J
v= 12.64 m/s
Explanation:
Given that
H= 12 m
m = 0.5 kg
h= 4 m
The potential energy at position 1
U₁ = m g H
U₁ = 0.5 x 10 x 12 ( take g= 10 m/s²)
U₁ = 60 J
The potential energy at position 2
U₂ = m g h
U ₂= 0.5 x 10 x 4 ( take g= 10 m/s²)
U₂ = 20 J
The kinetic energy at position 1
KE= 0
The kinetic energy at position 2
KE= 1/2 m V²
From energy conservation
U₁+KE₁=U₂+KE₂
By putting the values
60 - 20 = KE₂
KE₂ = 40 J
lets take final velocity is v m/s
KE₂= 1/2 m v²
By putting the values
40 = 1/2 x 0.5 x v²
160 = v²
v= 12.64 m/s