Normal force, friction force, gravitational force
The two most common units of electric energy is Watts or hertz.
D. It must be able to be magnetized
Explanation:
The requirement for a core to be used in an electromagnet is that it must be able to be magnetized.
An electromagnet is a type of magnet produced by electricity.
- They typically run and produce magnetic fields in the vicinity of electrical currents.
- These magnets are not permanent magnets.
- When the electrical current is removed, the magnetic property of the substance is lost.
- The core of an electromagnet is usually made up of a material that can easily be magnetized in the presence of magnetic fields.
- Some of the materials used are cobalt, iron, nickel.
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Answer:
c)the gravitational forces of people is so small it is overshadowed by that of earth.
Explanation:
The gravitational force between two objects is given by:

where
G is the gravitational constant
m1 and m2 are the masses of the two objects
r is the distance between the two objects
From the formula, we see that the gravitational force depends on the masses of the objects: since the mass of the Earth (
is much much larger than the average mass of one person (80-100 kg), then the gravitational force exerted by the Earth on a person is also much much larger than the gravitational force between two people.