Answer:

Explanation:
The formula for potential energy is:

where <em>m </em>is the mass, <em>g</em> is the gravitational acceleration, and <em>h</em> is the height.
The mass of the book is 0.4 kilograms. The gravitational acceleration on Earth is 9.8 m/s². The height of the book is 2 meters.

Substitute the values into the formula.

Multiply the first two numbers.
- 0.4 kg*9.8 m/s²= 3.92 kg*m/s²
- If we convert the units now, the problem will be much easier later on.
- 1 kg*m/s² is equal to 1 Newton. So, our answer of 3.92 kg*m/s² is equal to 3.92 N

Multiply.
- 3.92 N* 2 m=7.84 N*m
- 1 Newton meter is equal to 1 Joule (this is why we converted the units).
- Our answer is equal to<u> 7.84 Joules.</u>

Answer:
Option (3)
Explanation:
Nicolaus Copernicus was an astronomer from Poland, who was born on the 19th of February in the year 1473. He played a great role in the field of modern astronomy.
He was the person who contributed to the heliocentric theory. This theory describes the position of the sun in the middle of the universe, and all the planets move around the sun. This theory was initially not accepted, and after about a century it was widely accepted.
This theory describes the present-day motion of the planets around the sun in the solar system. This theory replaced the geocentric theory.
Thus, the correct answer is option (3).
Action-reaction pairs.
This is in reference to Newton’s second law of motion.
I guess it’s d) isobaric mate correct me if I am wrong :D
The ammonium salt of acetic acid is the reaction product of acetic acid and ethylamine at room temperature
<h3 /><h3>What is acetic acid ?</h3>
Acetic acid is a monofunctional carboxylic acid containing two carbon atoms. It acts as a protein solvent, food acidity regulator, antibacterial food preservative. It is a conjugate acid of an acetate.
Acetic acid is used in the production of acetic anhydride, cellulose acetate, vinyl acetate monomer, acetic ester, chloroacetic acid, plastics, dyes, insecticides, photographic chemicals, and rubber. Other commercial uses include the production of vitamins, antibiotics, hormones, organic chemicals, and as a food additive. Typical concentrations of acetic acid found naturally in foods are 700 to 1200 milligrams/kg (mg/kg) in wine, up to 860 mg/kg in aged cheeses, and 2.8 mg/kg in aged cheeses. fresh orange juice.
learn more about acetic acid, visit;
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