Answer:
a. 
b. 
c. 
Explanation:
a) The average of this values is the sum each number divided by the total number of values.

is values of each diameter- N is the total number of values. N=6


b) The standard deviation equations is:

If we put all this values in that equation we will get:

Then the mean diameter will be:
c) We know that the density is the mass divided by the volume (ρ = m/V)
and we know that the volume of a cylinder is: 
Then:

Using the values that we have, we can calculate the value of density:

We need to use propagation of error to find the error of the density.
- δm is the error of the mass value.
- δd is the error of the diameter value.
- δh is the error of the length value.
Let's find each partial derivative:
1. 
2. 
3. 
Therefore:


So the density is:

I hope it helps you!
Answer:
f = 409 Hz
Explanation:
We have,
Length of the open organ pipe, l = 0.29 m
Frequency of vibration of second overtone, 
It is required to find the fundamental frequency of the pipe. For the open organ pipe, the frequency of second overtone is given by :

v is speed of sound
Let f is the fundamental frequency. It is given by :

The relation between f and f₂ can be written as :

So, the fundamental frequency of the pipe is 409 Hz.
m = mass of granite boulder = 20 g
c = specific heat of granite boulder = 0.79 J/gC
T₀ = initial temperature of granite boulder = 10 °C
T = final temperature of granite boulder = 29 °C
Q = heat gained by granite boulder as energy from the sun
heat gained by granite boulder is given as
Q = m c (T - T₀)
inserting the values
Q = (20) (0.79) (29 - 10)
Q = 300.2 J