Answer:
f1 = 12.90 Hz
Explanation:
To calculate the first harmonic frequency you use the following formula for n = 1:

( 1 )
It is necessary that the unist are in meters, then you have:
L: length of the string = 60cm = 0.6m
M: mass of the string = 0.05kg
T: tension on the string = 20 N
you replace the values of L, M and T in the expression (1) for getting f1:

Hence, the first harmonic has a frequency of 12.90 Hz
Answer:
(c) 97 dB sound intensity level
Explanation:
We have given the intensity of the loud car horn 
We know that 
Now the sound intensity level is given by
, which is nearly equal to 97
So the sound intensity level will be 97 dB
So option (c) will be the correct option
Answer:

Explanation:
The situation can be described by the Principle of Energy Conservation and the Work-Energy Theorem:

The work done on the ball due to drag is:


![W_{drag} = (0.599\,kg)\cdot (9.807\,\frac{m}{s^{2}} )\cdot (2.18\,m-3.10\,m)+\frac{1}{2}\cdot (0.599\,kg)\cdot [(7.05\,\frac{m}{s} )^{2}-(4.19\,\frac{m}{s} )^{2}]](https://tex.z-dn.net/?f=W_%7Bdrag%7D%20%3D%20%280.599%5C%2Ckg%29%5Ccdot%20%289.807%5C%2C%5Cfrac%7Bm%7D%7Bs%5E%7B2%7D%7D%20%29%5Ccdot%20%282.18%5C%2Cm-3.10%5C%2Cm%29%2B%5Cfrac%7B1%7D%7B2%7D%5Ccdot%20%280.599%5C%2Ckg%29%5Ccdot%20%5B%287.05%5C%2C%5Cfrac%7Bm%7D%7Bs%7D%20%29%5E%7B2%7D-%284.19%5C%2C%5Cfrac%7Bm%7D%7Bs%7D%20%29%5E%7B2%7D%5D)

In my opinion it's,
Sirius is brighter than Canopus