Answer:
a. 
b. 
c. 
Explanation:
First, look at the picture to understand the problem before to solve it.
a. d1 = 1.1 mm
Here, the point is located inside the cilinder, just between the wire and the inner layer of the conductor. Therefore, we only consider the wire's current to calculate the magnetic field as follows:
To solve the equations we have to convert all units to those of the international system. (mm→m)

μ0 is the constant of proportionality 
μ0=4πX10^-7 N*s2/c^2
b. d2=3.6 mm
Here, the point is located in the surface of the cilinder. Therefore, we have to consider the current density of the conductor to calculate the magnetic field as follows:
J: current density 
c: outer radius
b: inner radius
The cilinder's current is negative, as it goes on opposite direction than the wire's current.




c. d3=7.4 mm
Here, the point is located out of the cilinder. Therefore, we have to consider both, the conductor's current and the wire's current as follows:

As we see, the magnitud of the magnetic field is greater inside the conductor, because of the density of current and the material's nature. 
 
        
             
        
        
        
Answer:
Wavelength = 10 m
Explanation:
Given:
Speed = 100 m
Frequency = 10 Hz = 10 
To find : Wavelength = ?
We know that the relationship between wavelength λ, frequency f and speed v is given by the equation
     v = fλ
Therefore wavelength λ = v/f
                                         = 100 m / 10 m
 / 10 m
                                         = 10 m
Hence wavelength = 10 m
 
        
             
        
        
        
Answer
given,
weight of the oak board = 600 N
Weight of Joe = 844 N
length of board = 4 m
Joe is standing at 1 m from left side 
vertical wire is supporting at the end.
Assuming the system is in equilibrium
T₁ and T₂ be the tension at the ends of the wire
equating all the vertical force 
 T₁ + T₂ = 600 + 844
  T₁ + T₂ = 1444...........(1)
taking moment about T₂
  T₁ x 4 - 844 x 3 - 600 x 2 = 0
  T₁ x 4 = 3732
  T₁ = 933 N
from equation (1)
  T₂ = 1444 - 933
  T₂ = 511 N
 
        
             
        
        
        
the greater the <u>mass</u> of an object the more force is needed to cause acceleration
 
        
             
        
        
        
Answer:
I belive it would be "C"
Explanation:
If it was any of the other answers "B" it would instantly stop. "A" it would roll forever.