Which sentences describe central ideas of the video? Select all that apply.

A laser beam enters a 12.0 cm thick glass window at an angle of 33.0° from the normal. The index of refraction of the glass is 1

Alenkinab [10]

Answer:

The time is 0.563 ns.

Explanation:

Given that,

Index of refraction of glass = 1.41

Distance = 12.0 cm

Angle = 33.0°

We need to calculate the refraction angle

Using Snell's law

$n_{1}\sin\theta=n_{r}\sin\theta$

put the value into the formula

$1\times\sin33=1.41\sin\theta$

$\sin\theta=\dfrac{1\times\sin33}{1.41}$

$\theta=22.71^{\circ}$

We need to calculate the velocity of beam in glass

Using formula of velocity

$v=\dfrac{c}{n}$

Put the value into the formula

$v=\dfrac{3\times10^{8}}{1.41}$

$v=2.13\times10^{8}\ m/s$

We need to calculate the time

Using formula of distance

$v=\dfrac{d}{t}$

$t=\dfrac{12.0\times10^{-2}}{2.13\times10^{8}}$

$t=5.63\times10^{-10}\ sec$

$t=0.563\times10^{-9}\ sec$

$t=0.563\ ns$

Hence, The time is 0.563 ns.

6 0

3 years ago

Each of 100 identical blocks sitting on a frictionless surface is connected to the next block by a massless string. The first bl

o-na [289]

Answer:

The tension in the string connecting block 50 to block 51 is 50 N.

Explanation:

Given that,

Number of block = 100

Force = 100 N

let m be the mass of each block.

We need to calculate the net force acting on the 100th block

Using second law of newton

$F=ma$

$100=100m\times a$

$ma=1\ N$

We need to calculate the tension in the string between blocks 99 and 100

Using formula of force

$F_{100-99}=ma$

$F_{100-99}=1$

We need to calculate the total number of masses attached to the string

Using formula for mass

$m'=(100-50)m$

$m'=50m$

We need to calculate the tension in the string connecting block 50 to block 51

Using formula of tension

$F_{50}=m'a$

Put the value into the formula

$F_{50}=50m\times a$

$F_{50}=50\times1$

$F_{50}=50\ N$

Hence, The tension in the string connecting block 50 to block 51 is 50 N.

8 0

3 years ago

The tallest building in the world, according to some architectural standards, is the Taipei 101 in Taiwan, at a height of 1671 f

Andrej [43]

Answer:

35.14°C

Explanation:

The equation for linear thermal expansion is $\Delta L = \alpha L_0\Delta T$ , which means that a bar of length $L_0$ with a thermal expansion coefficient $\alpha$ under a temperature variation $\Delta T$ will experiment a length variation $\Delta L$ .

We have then $\Delta L$ = 0.481 foot, $L_0$ = 1671 feet and $\alpha$ = 0.000013 per centigrade degree (this is just the linear thermal expansion of steel that you must find in a table), which means from the equation for linear thermal expansion that we have a $\Delta T =\frac{\Delta L }{\alpha L_0}$ = 22.14°. As said before, these degrees are centigrades (Celsius or Kelvin, it does not matter since it is only a variation), and the foot units cancel on the equation, showing no further conversion was needed.