<h2>
Answer:</h2>
Time
<h2>
Explanation:</h2>
The average speed of an object that is moving is defined as the distance traveled divided by the time of travel. You can measure the distance with a ruler and the time with a stopwatch. This can be expressed as the following formula:
For instance, if an object travels a distance 
in 4 seconds, the the average speed is:
<span>Self-dispatch to another incident</span>
Answer:
O²⁻
Explanation:
Number of protons = 8
Number of neutrons = 9
Number of electrons = 10
What type of atom or ion is it = ?
Solution:
Protons are the positively charged particle in an atom
Neutrons do not carry any charges
Electrons are negatively charged particles
For this atom, the number of protons helps to identify what specie it is; so this is an oxygen atom.
Now,
Charge = Number of protons - Number of electrons
Charge = 8 - 10 = -2
The charge on the atom is -2 and so it is an oxygen ion with -2 charge
The ion is O²⁻
Answer:
fo = 378.52Hz
Explanation:
Using Doppler effect formula:
where
f' = 392 Hz
C = 340m/s
Vb = 20m/s
Va = 31m/s
Replacing these values and solving for fo:
fo = 378.52Hz
