<span>b. The coefficient of static friction for all contacting surfaces is μs=0.35. neglect friction at the rollers.
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The initial position of the object was found to be 134.09 m.
<u>Explanation:</u>
As displacement is the measure of difference between the final and initial points. In other words, we can say that displacement can be termed as the change in the position of the object irrespective of the path followed by the object to change the path. So
Displacement = Final position - Initial position.
As the final position is stated as -55.25 meters and the displacement is also stated as -189.34 meters. So the initial position will be
Initial position of the object = Final position-Displacement
Initial position = -55.25 m - (-189.34 m) = -55.25 m + 189.34 m = 134.09 m.
Thus, the initial position for the object having a displacement of -189.34 m is determined as 134.09 m.
Answer:
N= 3
Explanation:
For this exercise we must use Faraday's law
E = - dФ / dt
Ф = B . A = B Acos θ
tje bold indicate vectors. As it indicates that the variation of the field is linear, we can approximate the derivatives
E = - A cos θ (B - B₀) / t
The angle enters the magnetic field and the normal to the area is zero
cos 0 = 1
A = π r²
In the length of the wire there are N turns each with a length L₀ = 2π r
L = N (2π r)
r = L / 2π N
we substitute
A = L² / (4π N²)
The magnetic field produced by a solenoid is
B = μ₀ N/L I
for which
B₀ = μ₀ N/L I
The final field is zero, because the current is zero
B = 0
We substitute
E = - (L² / 4π N²) (0 - μ₀ N/L I) / t
E = μ₀ L I / (4π N t)
N = μ₀ L I / (4π t E)
The electromotive force is E = 0.80 mV = 0.8 10⁻³ V
let's calculate
N = 4π 10⁻⁷ 200 1.60 / (4π 0.120 0.8 10⁻³)]
N = 320 10⁻⁷ / 9.6 10⁻⁶
N = 33.3 10⁻¹
N= 3
The answer for this question, If I am correct, should be answer "D".
