Answer:
the frequency of the second harmonic of the pipe is 425 Hz
Explanation:
Given;
length of the open pipe, L = 0.8 m
velocity of sound, v = 340 m/s
The wavelength of the second harmonic is calculated as follows;
L = A ---> N + N--->N + N--->A
where;
L is the length of the pipe in the second harmonic
A represents antinode of the wave
N represents the node of the wave

The frequency is calculated as follows;

Therefore, the frequency of the second harmonic of the pipe is 425 Hz.
Answer:
The answer is A. C and O..
The seventh planet from the sun is Uranus.
C is the answer because it mix and water combining together
Explanation:
potential energy = mass × gravity force × height
=20 × 10 × 25
= 5000 joules