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3 years ago

If a train going 80 m/min hits the

Physics

2 answers:

Ilia_Sergeevich [38]3 years ago

6 0

Answer:

-0.53 m/s²

Explanation:

Acceleration is the change in velocity over change in time.

a = Δv / Δt

First, convert m/min to m/s.

80 m/min × (1 min / 60 s) = 1.33 m/s

a = (0 m/s − 1.33 m/s) / 2.5 s

a = -0.53 m/s²

Arisa [49]3 years ago

5 0

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An ultrasonic tape measure uses frequencies above 20 MHz todetermine dimensions of structures such as buildings. It does so byem

ohaa [14]

Answer:

a) 1m

b) 2μs

c) 3mm

Explanation:

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3 years ago

All of the waves in the electromagnetic spectrum are _______ waves.

user100 [1]

Transverse, I think. I may be wrong.

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3 years ago

Read 2 more answers

The wavelength of red helium-neon laser light in air is 632.8 nm.(a) What is its frequency? Hz(b) What is its wavelength in glas

vekshin1

<h2>Answers:</h2>

The speed of a wave is given by:

$v=f.\lambda$ (1)

Where $f$ is the frequency and $\lambda$ the wavelength.

In the case of light, its speed is:

$c=f.\lambda$ (2)

On the other hand, the described situation is known as Refraction, a phenomenon in which the light changes its direction when passing through a medium with a refractive index different from the other medium.

In this context, the Refractive index $n$ is a number that describes how fast light propagates through a medium or material, and is defined as the relation between the speed of light in vacuum ( $c=3(10)^{8}m/s$ ) and the speed of light $v$ in the second medium:

$n=\frac{c}{v}$ (3)

In addition, as the light changes its direction, its wavelength changes as well:

$n=\frac{\lambda_{air}}{\lambda_{glass}}$ (4)

Knowing this, let's begin with the answers:

<h2>a) Frequency</h2>

From equation (2) we can find $f$ :

$f=\frac{c}{\lambda}$ (5)

Knowing that $1nm=(10)^{-9}m$ :

$f=\frac{3(10)^{8}m/s}{632.8(10)^{-9}m}$

$f=4.74(10)^{14}Hz}$ (6) >>>Frequency of the helium-neon laser light

<h2>b) Wavelength in glass</h2>

We already know the wavelength of the light in air $\lambda_{air}$ and the index of refraction of the glass.

So, we only have to find the wavelength in glass $\lambda_{glass}$ from equation (4):

$\lambda_{glass}=\frac{\lambda_{air}}{n}$

$\lambda_{glass}=\frac{632.8(10)^{-9}m}{1.48}$

$\lambda_{glass}=427(10)^{-9}m=427nm$ (7) >>>Wavelength of the helium-neon laser light in glass

<h2>c) Speed in glass</h2>

From equation (3) we can find the speed $v$ of this light in glass:

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

$v=\frac{3(10)^{8}m/s}{1.48}$

$v=2.027(10)^{8}m/s$ (8) >>>Speed of the helium-neon laser light in glass

7 0

3 years ago

Mark all the fermions a) Proton b) Electron c)Anti-top d) Gluon e) Tau Neutrino

aliya0001 [1]

Answer:

(a) Proton, (b) Electron (c) tau neutrino.

Explanation:

Elementary particles are the particles without any sub-structure which means they are not composed of other particles.

The elementary particles are classified into three categories which are discussed below:

(1) Quarks: up, down, top, bottom, strange, and charm.

(2) Leptons: electrons, electron neutrino, muon, muon neutrino, tau, tau neutrino.

(3) Bosons: Guon, photons Z bosons, W bosons, Higgs.

Fermions are particles that follow Fermi-Dirac statistics. Fermions consist of all the quarks and leptons. And fermions can also be categorized in elementary particles such as electrons and protons.

Therefore, the fermions in the given question are proton, electron, and tau neutrino.

5 0

3 years ago

A weight is hung from the ceiling of an elevator by a massless string. Under which circumstances will the tension in the cord be

Oduvanchick [21]

When the elevator is going up (assuming the elevator is acceleration)

When the elevator is accelerating downwards, the total gravitational force would be larger.

If the elevator is accelerating upwards, then the gravitation force would be smaller, thus the tension in the string would be smaller.

4 0

3 years ago