Complete Question
The complete question is shown on the first uploaded image
Answer:
The work done by the spring is = 
Explanation:
Force = torque × length
Given
F = 9.13 N
length (L) = 5.91 cm = 0.0591 m [Note 1 m = 100 cm ]
considering the formula above
where k denotes torque

Energy Stored 

There is still air inside of a house, which is pushing the roof upwards, so the forces are equal and the roof is not crushed.
Answer:
346.66 Hz
Explanation:
= Length of string which is unfingered = l
= Length of string which is vibrate when fingered = 
= Unfingered frequency = 260 Hz
= Fingered frequency
Frequency is inversely proportional to length

So,

The frequency of the fingered string is 346.66 Hz
Answer: D. 0.57
Explanation:
The formula to calculate the eccentricity
of an ellipse is (assuming the moon's orbit in the shape of an ellipse):

Where:
is the apoapsis (the longest distance between the moon and its planet)
is the periapsis (the shortest distance between the moon and its planet)
Then:


This is the moon's orbital eccentricity
A) 1.55
The speed of light in a medium is given by:

where
is the speed of light in a vacuum
n is the refractive index of the material
In this problem, the speed of light in quartz is

So we can re-arrange the previous formula to find n, the index of refraction of quartz:

B) 550.3 nm
The relationship between the wavelength of the light in air and in quartz is

where
is the wavelenght in quartz
is the wavelength in air
n is the refractive index
For the light in this problem, we have

Therefore, we can re-arrange the equation to find
, the wavelength in air:
