Utilizing Einstein's equation that signifies the relationship between mass and energy:

where
E stands for energy
m represents the object's rest mass
and c denotes the speed of light
By applying this formula and using m=2.5 kg, we can compute the object's equivalent energy:
When air is forced into the open pipe,
L = 
where n represents any whole number such as 1,2,3,4, etc., and λ denotes the wavelength of the oscillation
This implies λ=
It is important to note that n=1 corresponds to the fundamental frequency, n=2 corresponds to the first harmonic, and so forth.
Thus, the third harmonic will be for n=4
With L=6m and n=4, solving for λ yields:
λ=
=3m
The connection between frequency (f), sound speed (c), and wavelength (λ) is given by:
c=f.λ or f= 
Therefore, f=

≈115 Hz
<span>Let Q be the charge, thus Q = -20.0 µC.</span>
Define D as the distance between the center of the rod and the specified point. Therefore,
D=0.32 - 0.12 = 0.2 m
<span>L = 0.12 m, which represents the length of the rod
</span><span>To find the magnitude and direction of the electric field along the axis of the rod at a point 32.0 cm from its center, use the formula:
</span><span>E = K·Q/r²
</span>or<span>E = kQ/D(D+L), where k</span> is a constant equal to 8.99 x 10<span>9</span> N m
2/C2.<span>Consequently,[TAG_21]]E=(</span>8.99 x 109 N m2/C2.* (-20.0 µC))/(<span>0.2 m*0.32m)</span><span>
</span>