Answer:
I believe that the correct answer is D. reference point.
The answer is 0m because at point 8s the displacement is at zero m for example at 3s the displacement is at 8m
D because it has the lowest wavelength, meaning the wave is the longest. Its crest are more spaced out creating lower energy. The smaller distance between the crests equals the higher the sound. Creating higher energy.
I am 95% sure this is right. Very sorry if it isn't.
Hope it helps. ;3
(a) 423 J
The power of the battery is the ratio between the total energy stored (E) and the time elapsed (t):

However, the power is also the product of the voltage (V) and the current (I):

Linking the two equations together,

Since we know:
V = 9.0 V

We can calculate the total energy:

(b)
dollars
The battery has a total energy of E = 423 J. (2)
1 Watt (W) is equal to 1 Joule (J) per second (s):

so 1 kW corresponds to 1000 J/s:

Multiplying both side by 1 hour (1 h):

and
, so

So we find the conversion between kWh and Joules. So now we can convert the energy from Joules (2) into kWh:

And since the cost is $0.0660 per kilowatt-hour, the total cost will be
dollars
Answer:
Newton's second law of motion can be formally stated as follows: The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object.
Explanation: