CO₃
Explanation:
The polyatomic ion in the compound CaCO₃ is CO₃.
A polyatomic ion is an ion that is made up of more than one atom that has singular property.
They are usually called radicals.
CaCO₃ ⇒ Ca²⁺ + CO₃²⁻
CO₃²⁻ is a polyatomic ion because it is made up of more than one atom.
The CO₃²⁻ is called a carbonate group.
It is made up of:
- one atom of carbon
- 3 atoms of oxygen
- a net charge of 2-
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Answer:
70.07 Hz
Explanation:
Since the sound is moving away from the observer then
and 
when moving towards observer
With 
of 76 then taking speed in air as 343 m/s we have
Similarly, with of 65 we have
Now
v_s=27.76 m/s
Substituting the above into any of the first two equations then we obtain
Answer:
B) electrons
Explanation:
When charge is transferred by friction, induction or conduction, the charge carriers are the electrons.
In fact, protons and neutrons are found within the nucleus of the atoms, so they are tightly bound and they cannot be easily gained/given off. On the contrary, electrons are found in the electron clouds around the nucleus, so atoms can more easily gain/lose electrons, which become free and can be passed by an object to another.
The three methods of charging are:
- Friction: by rubbing two objects together, electrons may be transferred from one to another
- Induction: by moving a charged object closer to a neutral object, opposite charges in the neutral object migrate towards the opposite ends of the object, and if the object is connected to the ground, the charges of one polarity leave the object, leaving the object charged
- Conduction: by putting a charged object in contact with a neutral object, electrons can be transferred from the charged object to the neutral one
Answer : C. Pascal's principle.
Explaination : Pascal's principle (well-known as Pascal's law) states that if a closed container contains a fluid at rest, then a small change in pressure at one side of the fluid is transmitted to each and every part of the fluid and also to the walls of the container without any loss. In a hydraulic lift, we need the same mechanism to work and so we take the help of Pascal's principle.
Hence, the correct option is C. Pascal's principle.
Answer:
Explanation:
The center of mass of the system (two girls) is constant, as the velocity of the center of mass of the system is also constant.
<u>The initial velocity of the system is zero, since both girls are at rest.</u> So the velocity of the total system at any point should be zero as well.
This is true, because there is no friction between the girls and the ground. Otherwise, the velocity of the center of mass wouldn't be constant.
