Answer:
mass
Explanation:
mass is the answer to your question
I dont see a question 38 for the second one
Answer:
dV/dt = 9 cubic inches per second
Explanation:
Let the height of the cylinder is h
Diameter of cylinder = height of the cylinder = h
Radius of cylinder, r = h/2
dh/dt = 3 inches /s
Volume of cylinder is given by

put r = h/2 so,

Differentiate both sides with respect to t.

Substitute the values, h = 2 inches, dh/dt = 3 inches / s

dV/dt = 9 cubic inches per second
Thus, the volume of cylinder increases by the rate of 9 cubic inches per second.
Here is the main thing is medium. In the free boundary wave face the air medium, but in a fixed boundary wave face different medium. The change of medium effect on the change of the reflection of wave.