A mirror is opaque you can not see through it but you can see a reflection within it
Answer:
0.04455 Hz
Explanation:
Parameters given:
Wavelength, λ = 6.5km = 6500m
Distance travelled by the wave, x = 8830km = 8830000m
Time taken, t = 8.47hours = 8.47 * 3600 = 30492 secs
First, we find the speed of the wave:
Speed, v = distance/time = x/t
v = 8830000/30492 = 289.58 m/s
Frequency, f, is given as velocity divided by wavelength:
f = v/λ
f = 289.58/6500
f = 0.04455 Hz
Answer:
![1.81263\times 10^{27}\ kg](https://tex.z-dn.net/?f=1.81263%5Ctimes%2010%5E%7B27%7D%5C%20kg)
Explanation:
G = Gravitational constant = 6.67 × 10⁻¹¹ m³/kgs²
M = Mass of the star
m = Mass of object at a distance r
r = Radius = 25 km
N = 14 rev/s
The gravitational force of will balance the centripetal acceleration
![\dfrac{GMm}{r^2}=\dfrac{mv^2}{r}](https://tex.z-dn.net/?f=%5Cdfrac%7BGMm%7D%7Br%5E2%7D%3D%5Cdfrac%7Bmv%5E2%7D%7Br%7D)
Velocity is given by
![v=r\omega](https://tex.z-dn.net/?f=v%3Dr%5Comega)
![\dfrac{GMm}{r^2}=\dfrac{mr^2\omega^2}{r}\\\Rightarrow M=\dfrac{r^3\omega^2}{G}\\\Rightarrow M=\dfrac{25000^3\times (14\times 2\pi)^2}{6.67\times 10^{-11}}\\\Rightarrow M=1.81263\times 10^{27}\ kg](https://tex.z-dn.net/?f=%5Cdfrac%7BGMm%7D%7Br%5E2%7D%3D%5Cdfrac%7Bmr%5E2%5Comega%5E2%7D%7Br%7D%5C%5C%5CRightarrow%20M%3D%5Cdfrac%7Br%5E3%5Comega%5E2%7D%7BG%7D%5C%5C%5CRightarrow%20M%3D%5Cdfrac%7B25000%5E3%5Ctimes%20%2814%5Ctimes%202%5Cpi%29%5E2%7D%7B6.67%5Ctimes%2010%5E%7B-11%7D%7D%5C%5C%5CRightarrow%20M%3D1.81263%5Ctimes%2010%5E%7B27%7D%5C%20kg)
The mass of the neutron star is ![1.81263\times 10^{27}\ kg](https://tex.z-dn.net/?f=1.81263%5Ctimes%2010%5E%7B27%7D%5C%20kg)
sorry accidentally posted here.