Answer:
They have same density
Explanation:
The density of an object is defined as
where
m is the mass of the object
V is its volume
Let's call 
and 
the mass and the volume of ball C, respectively. Therefore, the density of ball C is:
We know that the volume of ball C is 3 times the volume of ball D, so
And we also know that ball D has 1/3 the mass of ball C:
So, the density of ball D is:
Therefore, the two balls have same density.
<h3><u>Answer;</u></h3>
= 0.0000001 mol/L
= 0.0000001 mol/L
= 1:1
<h3><u>Explanation;</u></h3>
What is the concentration of H+ ions at a pH = 7?
The formula for ph is given by:
pH=−log10[H+]
In calculating for the concentration of hydrogen ion, the formula is given by:
[H+]=(10)^(-pH)
Therefore; at pH = 7
[H+]=(10)^(-7)
<u>= 0.0000001 mol/L </u>
What is the concentration of OH– ions at a pH = 7?
pH+pOH=14
7+pOH=14
pOH= 7
[OH-]=(10)^(-pOH)
[OH-]=(10)^(-7)
<u>= 0.0000001 mol/L </u>
What is the ratio of H+ ions to OH– ions at a pH = 7?
1:1
Power is defined by the rate of work done by the object. Statement D represents the correct definition of Power.
<h3>What is Power?</h3>
Power can be defined as the transfer of energy from one place to another place. The rate at which this energy is transferred is called power.
In other words, the rate at which the work is done by an object is called its power. The mathematical representation of power is given as,
Here, P is the power, 
is the change in energy or work done and 
change in time.
The Power can be written in SI units as Watt or J/s.
Hence we can conclude that the power is the rate at which work is accomplished. Statement D is the correct representation of Power.
To know more about power, follow the link given below.
brainly.com/question/1618040.
Answer:
The Doppler shift may be helpful to determine the relative speed of an object by bouncing a wave (usually a radar wave) off the object and measuring the shift in the frequency of the wave.
Explanation:
Doppler shift helps to overcome a visual illusion block out irrelevant noises, locate sounds and see an object in very dim light by determining the relative speed of an object by bouncing a wave
A vehicle should never be parked closer to a fire hydrant than: <span>15 feet
Fire hydrants are reserved by the government as the source of water for the fire department to put out the fire during a burning accident.
If you put your vehicle too close to the hydrant, it could potentially block the process during an emergency situation and could cost us humans' life.</span>
