Which of these diagrams most accurately illustrates what happens when a ray of light from underwater strikes the smooth surface
of the water at an angle of incidence greater than the critical angle?
2 answers:
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Answer:
47.4 m
Explanation:
When an object is thrown upward, it rises up, it reaches its maximum height, and then it goes down. The time at which it reaches its maximum height is half the total time of flight.
In this case, the time of flight is 6.22 s, so the time the ball takes to reach the maximum height is
Now we consider only the downward motion of the ball: it is a free fall motion, so we can find the vertical displacement by using the suvat equation
where
s is the vertical displacement
u = 0 is the initial velocity
t = 3.11 s is the time
is the acceleration of gravity (taking downward as positive direction)
Solving the formula, we find
The thermal expansion of the materials allows to find the deflection of the bimetallist strip is Δy = 3.48 cm
given paramers
* Bimetallic brass / steel tape
* Initial temperature, room temperature T = 20ºC
* Final temperature, boiling water = 100ºC
* initial length L₀ = 222mm (1cm / 10mm) = 22.2cm
* thickness of bimetallic tape e = 0.036 inch (2.54 cm/1 inch) = 0.0914 cm
to find
* perpendicular deviation or deflection (Δy)
Thermal expansion is the phenomenon of change in the length of a body due to the change in temperature, due to the increase in the length of the atomic and molecular bonds, macroscopically it is described by
ΔL = α L₀ ΔT
ΔL and ΔT are the variation of the length and temperature respectively, L₀ is the initial length and α the coefficient of expansion ends.
In this case we have a strip formed by two materials with different coefficient of thermal expansion,
Brass α_{brass} = 19 10⁻⁶ ºC⁻¹
Steel α_{steel} = 11 10⁻⁶ ºC⁻¹
In the attached we can see a diagram of the process, as the temperature increases, the material with greater thermal expansion lengthens more, so the system must curve towards the center of the material with less
thermal expansion. Let's find the length of the strip for each material
brass L_{f brass} - L₀ = α_{brass} L₀ ΔT
Steel L_{f steel} - L₀ = \alpha_{steel} L₀ ΔT
Note that the initial length is the same for the two materials and that the strip is in thermal equilibrium at room temperature.
If we assume that we have an arc of circumference, we can write the length of the arc
θ = L / r
where θ is the angle in radines, L the length of the arc and r the radius of curvature, let's write this equation for each material
brass L_{f \ brass} =θ r₁
steel L_{f \ steel} = θ r₂
we substitute in our equations
θ r₁ - L₀ = α_{brass} L₀ ΔT
θ r₂ - L₀ = α_{steel} L₀ ΔT
let's subtract the two equations
θ (r₁- r₂) = L₀ ΔT (α_{brass} - α_{steel})
the thickness of the strip is
e = r₁ -r₂
θ =
we calculate
θ =
θ = 0.155 rad
Let's use trigonometry to find the perpendicular deflection
tan θ = Δy / L₀
Δy = L₀ tan θ
Δy = 22.2 tan 0.155
Δy = 3.48 cm
Using the thematic expansion of the two materials we find the deflection of the bimetallist strip is 3.38 cm
Learn more about thermal expansion here: brainly.com/question/18717902
