I think the correct answer would be that because electromagnets are powerful and can be turned off and on anytime. Electromagnet is a magnet in which the magnetic field is made by the electric current that is induced to the system.
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:
Social media has helped many businesses grow and promote itself, and has helped people find a better way to connect and communicate with one another. On the other hand, it's also provided many people with problems involving mental health, emotional insecurities, and waste of time
Explanation:
what they said is correct
Answer:
1.42
Explanation:
<em> got it right on my homework </em>
Answer: The velocity of the ball is 30.0 m/s
This can be calculated by using the value of acceleration as 10.0 m/s2 in free fall and the given time of 3.0 seconds. To get the
velocity, one will have to multiply the acceleration with the given time and the
quotient would result to 30.0 m/s. Mostly all object regardless of their mass,
fall to earth with the same acceleration in the absence of air resistance and as
the child drops the ball from a window, it gains speed as it falls.