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3 years ago

7

Physics lenses/critical angle question need help ASAP

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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Which of the following best describes wind?

Afina-wow [57]

Answer:

The answer is D the rising of warm air pushing down cool air.

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3 years ago

A rope passes over a fixed sheave with both ends hanging straight down. The coefficient of friction between the rope and sheave

Oliga [24]

Answer:3.51

Explanation:

Given

Coefficient of Friction $\mu =0.4$

Consider a small element at an angle \theta having an angle of $d\theta$

Normal Force $=T\times \frac{d\theta }{2}+(T+dT)\cdot \frac{d\theta }{2}$

$N=T\cdot d\theta$

Friction $f=\mu \times Normal\ Reaction$

$f=\mu \cdot N$

and $T+dT-T=f=\mu Td\theta$

$dT=\mu Td\theta$

$\frac{dT}{T}=\mu d\theta$

$\int_{T_2}^{T_1}\frac{dT}{T}=\int_{0}^{\pi }\mu d\theta$

$\frac{T_2}{T_1}=e^{\mu \pi}$

$\frac{T_2}{T_1}=e^{0.4\times \pi }$

$\frac{T_2}{T_1}==e^{1.256}$

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3 years ago

Aristotle was a true scientist. True or false?

leonid [27]

No, because he was a philosopher

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4 years ago

Read 2 more answers

sladkih [1.3K]

Hello there!

I hope you and your family are staying safe and healthy during this unprecendented time.

A) What is the work done?

Answer: We need to use the formula

$w=-F_f(d)$

$w=-(35)(20)$

$w=-700J$

B) What is the work done on the cart by the gravitational force?

Alright, we know that the gravitional force is perpendicular to the diplacement. Therefore, we gonna use the following formula:

$w=Fdcos90$

$w=0$

C) What is the work done on the cart by the shopper?

This is the easier part, since we already know that the work done by the shopper is the same as the work done by the friction force

$W shopper + W friction = 0\\W shopper = W-friction \\W shopper = 700J$

D) Find the force the shopper exerts, using energy considerations.

$F_f+Fcos25=0\\-35+Fcos25=0\\F=38.6N$

E) What is the total work done?

You just need to add them:

$w=wshopper+wfriction\\w=0$

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3 years ago

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devlian [24]

Answer:

C

Explanation:

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3 years ago

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