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3 years ago

Physics lenses/critical angle question need help ASAP

Physics

1 answer:

zavuch27 [327]3 years ago

8 0

The answer should be B.

There are 2 conditions for total internal reflection:

Light travels from an optically denser medium to an optically less dense medium.
Angle of incidence (the angle between the incident ray and the normal) is greater than the critical angle.

For this question, light is travelling from glass to air, so the first condition is fulfilled. Yet, the angle of incidence is only 30°, which is less than the critical angle. Therefore, total internal reflection will not occur.

Instead, there will be refraction. Light ray bends away from normal when it is travelling to a less dense object, thus having a greater angle of refraction than the angle of incidence.

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$V=\frac{48km}{0.25hr}$

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$V_{wind}=(39.71i - 13.67j)km/hr$

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$V_{plane x}=V_{plane/wind x}+V_{wind x}$

$V_{plane/wind x}=V_{plane x}-V_{wind x}$

$V_{plane/wind x}=(0-39.71 i)km/hr$

$V_{plane/wind x}= -39.71 i km/hr$

and

$V_{plane y}=V_{plane/wind y}+V_{wind y}$

$V_{plane/wind y}=V_{plane y}-V_{wind y}$

$V_{plane/wind y}=192km/hr j - (- 13.67j)km/hr$

$V_{plane/wind x}= 205.67 j km/hr$

So the velocity of the plane with respect to the wind can be rewritten as:

$V_{plane/wind x}= (-39.71i + 205.67 j) km/hr$

Since the problem asks us to find the speed of the plane with respect to the wind, this means that we need to find the magnitude of the velocity, since the speed is a scalar defined to be the magnitude of the velocity.

so:

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