Answer:
he polarity of the electromagnet is determined by the direction the current. The north pole of the electromagnet is determined by using your right hand. Wrap your fingers around the coil in the same direction as the current is flowing (conventional current flows from + to -).
Explanation:
<span>Velocity, you divide distance/time </span>
Answer:
The center of mass for the object is
from the origin
Explanation:
From the question we are told that
The mass of the first object is 
The position of first object with respect to origin 
The mass of the second object is 
The position of second object with respect to origin 
The mass of the third object is 
The position of third object with respect to origin 
The mass of the fourth object is 
The position of fourth object with respect to origin 
Generally the center of mass of the object along the x-axis is zero because all the mass lie on the y axis
Generally the location of the center mass of the object is mathematically represented as

=>
=>
In solids: All metals are good conductors of electricity as they contain free moving electrons. Non-metals doesn't conduct , but we consider Graphite the only non-metal that can conduct electricity for the presence of free moving electrons.
In Liquids ; Ionic compunds contains free moving ions , so they conduct electricity as well .
High frequency = D, short wavelength