My dog Callie can run at 21 mi/h. How far can he travel in 10 hours?

Answer + Explanation:

To determine the hardness value of each rock, you need to follow the instructions provided and test the rocks with different substances. Here is a step-by-step guide:

1. Start by scratching the rock with your fingernail. If your fingernail can make a mark on the rock, record the related hardness value from the chart in your table. For example, if your fingernail scratches the rock and the corresponding hardness value in the chart is 2, you would record 2 in your table.

2. If your fingernail doesn't scratch the rock, move on to the next substance, which is a copper penny. Try scratching the rock with the copper penny. If the penny doesn't scratch the rock, move on to the next substance.

3. The next substance to try is a wire nail. Scratch the rock with the wire nail. If the wire nail doesn't scratch the rock, proceed to the last substance.

4. The last substance to try is a masonry nail. Scratch the rock with the masonry nail. If the masonry nail doesn't scratch the rock, record the highest value from the chart in your table.

By following these steps and recording the highest hardness value achieved through the scratching test with each substance, you will be able to determine the hardness value of each rock.

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Answer:

D. pushing a chair against the wall.

Explanation:

Final answer:

The last and longest manned mission to Skylab is a notable point in history of space exploration, but the specific duration is not stated in the provided references.

Explanation:

In regard to the question, "What was the duration of the last and longest manned mission to Skylab?", the Skylab missions were part of a significant chapter in U.S. space exploration history during the 1970s. However, the provided reference material does not offer specific information about the duration of the last and longest manned mission to Skylab. Skylab was an important part of American space research, serving as a space station where numerous scientific experiments were conducted. Yet, without the specific details, it is difficult to provide an accurate response to this particular query. The Skylab program, operated by NASA in the 1970s, had its last and longest manned mission known as Skylab 4. The Skylab 4 mission launched on November 16, 1973, and lasted for a total of 84 days, with the crew returning to Earth on February 8, 1974. The crew consisted of Gerald Carr, Edward Gibson, and William Pogue. This mission set a record for the longest manned spaceflight at that time, spending an extended period aboard the Skylab space station for scientific research and experiments.

Learn more about Skylab here:

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Answer:

The purpose of a core in an electromagnet is to enhance the magnetic field strength produced by the electromagnet. The core is typically made of a ferromagnetic material, such as iron or steel, that can easily magnetize and demagnetize.

When an electric current flows through a wire wrapped around the core, a magnetic field is generated. This magnetic field is concentrated and strengthened by the core material. The core acts as a pathway for the magnetic field lines to flow through, making the electromagnet stronger and more efficient.

The core helps to increase the magnetic flux density, which is the amount of magnetic field passing through a given area. By concentrating the magnetic field, the core allows the electromagnet to exert a stronger force on nearby magnetic objects, such as attracting or repelling other magnets or moving metal objects.

To visualize this, think of the core as a "magnetic conductor" that channels and focuses the magnetic field. It's like using a magnifying glass to concentrate sunlight onto a small spot, making it hotter and more intense. Similarly, the core enhances the strength of the magnetic field produced by the electromagnet.

In summary, the purpose of a core in an electromagnet is to increase the magnetic field strength by providing a pathway for the magnetic field lines to flow through. This makes the electromagnet more powerful and allows it to perform various tasks, such as lifting objects, generating electricity, or controlling mechanical devices.

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Answer:

Purpose of a core in an electromagnet to increase the strength, efficiency, and size of the magnetic field.

Explanation:

An electromagnet is a type of magnet in which the magnetic field is produced by an electric current. Electromagnets usually consist of wire wound into a coil. A current through the wire creates a magnetic field which is concentrated in the hole in the center of the coil.

The purpose of a core in an electromagnet is to concentrate the magnetic field.

The coil of wire that creates the magnetic field in an electromagnet is typically made of copper, which has a relatively low magnetic permeability. This means that the magnetic field lines tend to spread out in all directions, resulting in a weak magnetic field.

Some of the purposes of using a core in an electromagnet are:

• To increased magnetic field strength:
  The core concentrates the magnetic field, resulting in a much stronger magnetic field.
• To reduced size:
  The core helps to confine the magnetic field, which can reduce the size of the electromagnet.
• To improved efficiency:
  The core helps to direct the magnetic field, which can improve the efficiency of the electromagnet.

Overall, the core in an electromagnet plays an important role in increasing the strength, efficiency, and size of the magnetic field.

Answer:

Ions are atoms that carry an electric charge.

Explanation:

An ion is an atom or molecule that does not have a neutral electric charge. In other words, ions are atoms or groups of atoms that have an electric charge. Ions with a positive charge are called cations. Those with a negative charge are called anions.

Ionization is the formation of electrically charged molecules or atoms. Atoms are electrically neutral. The loss of one or more electrons from a neutral atom forms a cation. Conversely, an anion is an ion whose net charge is negative due to an increase in the number of electrons.

Cations and anions are usually represented with the symbol of the corresponding atom or group of atoms and the symbol "+" or "-", respectively. If the number of electrons gained or lost is greater than one, this is indicated by the corresponding number.

Answer:

Inertia

Explanation:

The tendency of an object to resist any change in its motion is known as its inertia. The first law of motion is also known as the law of inertia. The inertia of an object can change its speed and the direction of motion. It is related directly to the mass of an object.

A body having more mass will have more inertia while a body having less mas will have less inertia.