See for yourself how the forces of electricity and magnetism can work together by building a simple DC electric motor using simple materials you can find in any hardware store!
Electricity and magnetism are both forces caused by the movement of tiny charged particles that make up atoms, the building blocks of all matter. When a wire is hooked up to a battery, current flows through the wire because negatively charged electrons flow from the negative terminal of the battery toward the positive terminal of the battery because opposite charges attract each other, while similar charges repel each other. This flow of electrons through the wire is an electric current, and it produces a magnetic field.
In a magnet, atoms are lined up so that the negatively charged electrons are all spinning in the same direction. Like an electric current, the movement of the electrons creates a magnetic force. The area around the magnet where the force is active is called a magnetic field. Metal objects and other magnets that enter this field will be pulled toward the magnet.
The way the atoms are lined up creates two different poles in the magnet, a north pole and a south pole. As with electrical charges, opposite poles attract each other, while like poles repel each other.
Learn about electromagnetism and its many uses here.
Now let's watch it work as we build a motor.
(Note: This science project requires adult supervision.)
Answers:
a) 5400000 J
b) 45.92 m
Explanation:
a) The kinetic energy 
of an object is given by:
Where:
is the mass of the train
is the speed of the train
Solving the equation:
This is the train's kinetic energy at its top speed
b) Now, according to the Conservation of Energy Law, the total initial energy is equal to the total final energy:
Where:
is the train's initial kinetic energy
is the train's initial potential energy
is the train's final kinetic energy
is the train's final potential energy, where 
is the acceleration due gravity and 
is the height.
Rewriting the equation with the given values:
Finding :
Answer:
The power for circular shaft is 7.315 hp and tubular shaft is 6.667 hp
Explanation:
<u>Polar moment of Inertia</u>
= 0.14374 in 4
<u>Maximum sustainable torque on the solid circular shaft</u>
=
= 3658.836 lb.in
= 
lb.ft
= 304.9 lb.ft
<u>Maximum sustainable torque on the tubular shaft</u>
= 
= 3334.8 lb.in
= 
lb.ft
= 277.9 lb.ft
<u>Maximum sustainable power in the solid circular shaft</u>
= 
= 4023.061 lb. ft/s
= 
hp
= 7.315 hp
<u>Maximum sustainable power in the tubular shaft</u>
= 
= 3666.804 lb.ft /s
= 
hp
= 6.667 hp
Answer:
Voltage across the capacitor is 30 V and rate of energy across the capacitor is 0.06 W
Explanation:
As we know that the current in the circuit at given instant of time is
i = 2.0 mA
R = 10 k ohm
now we know by ohm's law
so voltage across the capacitor + voltage across resistor = V
Now we know that
here rate of change in energy of the capacitor is given as
