Compressional waves can travel through all states of matter.
Answer:
Part 1) Time of travel equals 61 seconds
Part 2) Maximum speed equals 39.66 m/s.
Explanation:
The final speed of the train when it completes half of it's journey is given by third equation of kinematics as
![v^{2}=u^2+2as](https://tex.z-dn.net/?f=v%5E%7B2%7D%3Du%5E2%2B2as)
where
'v' is the final speed
'u' is initial speed
'a' is acceleration of the body
's' is the distance covered
Applying the given values we get
![v^2=0+2\times 1.30\times \frac{1210}{2}\\\\v^{2}=1573\\\\\therefore v=39.66m/s](https://tex.z-dn.net/?f=v%5E2%3D0%2B2%5Ctimes%201.30%5Ctimes%20%5Cfrac%7B1210%7D%7B2%7D%5C%5C%5C%5Cv%5E%7B2%7D%3D1573%5C%5C%5C%5C%5Ctherefore%20v%3D39.66m%2Fs)
Now the time taken to attain the above velocity can be calculated by the first equation of kinematics as
![v=u+at\\\\v=0+1.30\times t\\\\\therefore t=\frac{39.66}{1.30}=30.51seconds](https://tex.z-dn.net/?f=v%3Du%2Bat%5C%5C%5C%5Cv%3D0%2B1.30%5Ctimes%20t%5C%5C%5C%5C%5Ctherefore%20t%3D%5Cfrac%7B39.66%7D%7B1.30%7D%3D30.51seconds)
Since the deceleration is same as acceleration hence the time to stop in the same distance shall be equal to the time taken to accelerate the first half of distance
Thus total time of journey equals![T=2\times 30.51\approx61seconds](https://tex.z-dn.net/?f=T%3D2%5Ctimes%2030.51%5Capprox61seconds)
Part b)
the maximum speed is reached at the point when the train ends it's acceleration thus the maximum speed reached by the train equals ![39.66m/s](https://tex.z-dn.net/?f=39.66m%2Fs)
It is strong enough to penetrate through flesh but not bone so we can see if there are fractures or breaks in our skeleton
It would be a good game for you but if I get a pic I don’t want you can you come to my crib I just
Answer:
![63.4^{\circ}](https://tex.z-dn.net/?f=63.4%5E%7B%5Ccirc%7D)
Explanation:
When unpolarized light passes through the first polarizer, the intensity of the light is reduced by a factor 1/2, so
(1)
where I_0 is the intensity of the initial unpolarized light, while I_1 is the intensity of the polarized light coming out from the first filter. Light that comes out from the first polarizer is also polarized, in the same direction as the axis of the first polarizer.
When the (now polarized) light hits the second polarizer, whose axis of polarization is rotated by an angle
with respect to the first one, the intensity of the light coming out is
(2)
If we combine (1) and (2) together,
(3)
We want the final intensity to be 1/10 the initial intensity, so
![I_2 = \frac{1}{10}I_0](https://tex.z-dn.net/?f=I_2%20%3D%20%5Cfrac%7B1%7D%7B10%7DI_0)
So we can rewrite (3) as
![\frac{1}{10}I_0 = \frac{1}{2}I_0 cos^2 \theta](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B10%7DI_0%20%3D%20%20%5Cfrac%7B1%7D%7B2%7DI_0%20cos%5E2%20%5Ctheta)
From which we find
![cos^2 \theta = \frac{1}{5}](https://tex.z-dn.net/?f=cos%5E2%20%5Ctheta%20%3D%20%5Cfrac%7B1%7D%7B5%7D)
![cos \theta = \frac{1}{\sqrt{5}}](https://tex.z-dn.net/?f=cos%20%5Ctheta%20%3D%20%5Cfrac%7B1%7D%7B%5Csqrt%7B5%7D%7D)
![\theta=cos^{-1}(\frac{1}{\sqrt{5}})=63.4^{\circ}](https://tex.z-dn.net/?f=%5Ctheta%3Dcos%5E%7B-1%7D%28%5Cfrac%7B1%7D%7B%5Csqrt%7B5%7D%7D%29%3D63.4%5E%7B%5Ccirc%7D)