Answer:
Sugar dissolves faster than salt
The speed of sound at

is approximately v=343 m/s. The distance covered by the sound wave is

And the time it takes is

Now we want to find how far the light travels during this time. Light travels at speed

, therefore the distance it covers during this time is
B. Move from their ground states up to excited states
:)
Kinetic energy per unit of mass is

Given, 
Therefore,


Now potential energy per unit mass is

Given, 
Therefore,


Thus, total mechanical energy of the river water per unit mass is


OR

Answer:
Explanation:
Make up a question.
The only change is going to be c.
Suppose they aluminum starts our higher at 50oC
Suppose the copper starts out at 20oC
Suppose the mass of both are 25 grams.
Aluminum
m*2c * deltat
- deltat = 50 - x
- c = 2*c
- m = 25
Copper
m*c*deltat
deltat = x - 20
m = 25
c = c
Now since the amount of heat is the same (this starts out on a heated slab of something).
m*2c * (50 - x) = m * c * x - 20 The m and the c are the same. Cancel them out.
2 * (50 - x) = (x - 20) Remove the brackets.
100 - 2x = x - 20 Add 20 to both sides.
120 - 2x = x Add 2x to both sides.
120 = 3x Divide by 3
x = 40
What does this tell you?
It tells you that the temperature of the aluminum is only going to drop 10 degrees
The copper is going to gain 40 - 20 = 20 degrees.
The heat transfer is actually the same. It doesn't take as much heat to heat copper as it does aluminum. That's shown by the difference in how the temperature changes. One looses 10 degrees. The other gains 20. The transfer is the same because of the way the "c" operates.