Answer: a) 8.2 * 10^-8 N or 82 nN and b) is repulsive
Explanation: To solve this problem we have to use the Coulomb force for two point charged, it is given by:
Replacing the dat we obtain F=82 nN.
The force is repulsive because the points charged have the same sign.
Answer:
Cd(NO3)2 + Na2S --> CdS + 2 NaNO3
Explanation:
Answer:A
Explanation:matter normally occurs in three phases;solid, liquid and gases. They may change from one phase to another due to temperature difference.
The molecules that makes up solids are held together by bonds. When heat is added,the molecules begin to move as a result,the bonds break and it turns to liquid.this process is called melting. The reverse of melting is freezing.
Liquid are made up of molecules that moves more freely than solids. When heat is added to liquid,the molecules gain more energy and begins to move faster. This causes them to turn to gases.
This process is called evaporation. It occurs at different temperature for different substances.
The particles of gases move more faster and are separated by large distances. A gas can change back to a liquid through condensation.
The pressure exerted on the table due to the book is 200 N/m².
The given parameters;
- <em>mass of the book, m = 400 g = 0.4 kg</em>
- <em>dimension of the table, = 0.10m x 0.20 m.</em>
- <em>gravitational field strength g = 10 N/kg.</em>
The area of the table is calculated as follows;
A = 0.1 x 0.2 = 0.02 m²
The pressure exerted on the table due to the book is calculated as follows;
where;
- <em>F is the force of the book due to its weight</em>
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Thus, the pressure exerted on the table due to the book is 200 N/m².
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