you're so beautiful!
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To solve this problem it is necessary to apply the concepts related to the Force since Newton's second law, as well as the concept of Electromagnetic Force. The relationship of the two equations will allow us to find the magnetic field through the geometric relations of density and volume.

Where,
B = Magnetic Field
I = Current
L = Length
<em>Note:
is a direct adaptation of the vector relation
</em>
From Newton's second law we know that the relation of Strength and weight is determined as

Where,
m = Mass
g = Gravitational Acceleration
For there to be balance the two forces must be equal therefore

Our values are given as,
Diameter 
Radius 
Magnetic Field 
From the relationship of density another way of expressing mass would be

At the same time the volume ratio for a cylinder (the shape of the wire) would be

Replacing this two expression at our first equation we have that:



Re-arrange to find I


We have for definition that the Density of copper is
, gravity acceleration is
and the values of magnetic field (B) and the radius were previously given, then:


The current is too high to be transported which would make the case not feasible.
Explanation:
Using Ohm's Law and a bit of substitution, we can use voltage divided by current to solve for resistance. Doing that, we'll get 6 Ohm.
Complete Question
The complete question is shown on the first and second uploaded image
Answer:
The velocity is
Explanation:
The kinetic energy of the 9 kg can be determined by these expression
Kinetic energy of 9 kg block = initial energy stored - energy lost as a result of friction
Now to obtain the initial energy stored
Let U denote the initial energy stored and

Where x is the length the spring is displaced
k is the force constant of the string


Now referring to the formula above
i.e Kinetic energy of 9 kg block = initial energy stored - energy lost as a result of friction



and we are told that coefficient of friction = 0.4 and the mass is 9 kg ,the acceleration due to gravity
this displacement length of spring = 0.6
Therefore 
Answer:
0.048J/g°C
Explanation:
Given parameters:
Mass of Mercury = 25g
Initial temperature = 25°C
Final temperature = 155°C
Amount of heat absorbed = 455J
Unknown:
Specific heat capacity of mercury = ?
Solution:
To solve this problem, we use the expression below:
Q = m x C x Δt
Q is the heat absorbed
m is the mass
C is the unknown specific heat capacity
Δt is the change in temperature;
455 = 25 x C x (155 - 25)
455 = 25 x C x 130
C = 0.048J/g°C