A distant galaxy is observed to have its hydrogen-E line shifted to a wavelength of 580 nm, away from the laboratory value of 43
4 nm. Which of the following gives the approximate velocity of recession of the distant galaxy? (Note: LaTeX: \frac{580}{434} \approx \frac{4}{3} )c
a. 0.53c
b. 0.28c
c. 0.86c
d. 0.56c
a. 0.53c
b. 0.28c
c. 0.86c
d. 0.56c
1 answer:
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Answer:
v₂ = 0.56 m / s
Explanation:
This exercise can be done using Bernoulli's equation
P₁ + ½ ρ v₁² + ρ g y₁ = P₂ + ½ ρ v₂² + ρ g y₂
Where points 1 and 2 are on the surface of the glass and the top of the straw
The pressure at the two points is the same because they are open to the atmosphere, if we assume that the surface of the vessel is much sea that the area of the straw the velocity of the surface of the vessel is almost zero v₁ = 0
The difference in height between the level of the glass and the straw is constant and equal to 1.6 cm = 1.6 10⁻² m
We substitute in the equation
+ ρ g y₁ =
+ ½ ρ v₂² + ρ g y₂
½ v₂² = g (y₂-y₁)
v₂ = √ 2 g (y₂-y₁)
Let's calculate
v₂ = √ (2 9.8 1.6 10⁻²)
v₂ = 0.56 m / s