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3 years ago

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Dois carros, a e b, móveis se em uma estrada retilínea com volocidade constante,vª =20m/s e v=18 m/s , respectivamente. O carro

A ,está, inicialmente, 500m atrás do carro B . Quanto tempo o carro A levará para alcançar o carro B?

1 answer:

LekaFEV [45]3 years ago

4 0

I just need some points

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Please help!! For a science quiz

klio [65]

1.Velocity (v) is a vector quantity that measures displacement (or change in position, Δs) over the change in time (Δt), represented by the equation v = Δs/Δt. Speed (or rate, r) is a scalar quantity that measures the distance traveled (d) over the change in time (Δt), represented by the equation r = d/Δt.

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3 years ago

A hammer taps on the end of a 5.0-mm-long metal bar at room temperature. A microphone at the other end of the bar picks up two p

katrin2010 [14]

Answer:

810.37 m/s

Explanation:

s = Displacement = 5 m

$v_a$ = Speed of sound in air = 343 m/s

Time taken to travel the distance

$t'=\dfrac{s}{v_a}\\\Rightarrow t'=\dfrac{5}{343}\\\Rightarrow t'=0.01457\ s$

Time for the sound in metal

$t=0.01457-8.4\times 10^{-3}=0.00617\ s$

Speed of sound is given by

$v=\dfrac{s}{t}\\\Rightarrow v=\dfrac{5}{0.00617}\\\Rightarrow v=810.37277\ m/s$

The speed of sound in the metal is 810.37 m/s

6 0

3 years ago

What is the wavelength of light that is deviated in the first order through an angle of 13.1 ∘ by a transmission grating having

faltersainse [42]

Answer:

The wavelength of light is $4.53\times10^{-7}\ m$

Explanation:

Given that,

Angle = 13.1°

Number of slits = 5000

We need to calculate the wavelength of light

Diffraction of first order is defined as,

$d \sin\theta=n\lambda$ .....(I)

The separation of the slits

$d = \dfrac{1}{N}$

$d=\dfrac{1}{5000}$

$d=2\times10^{-6}\ m$

Now put the value in equation (I)

$2\times10^{-6}\sin13.1^{\circ}=\lambda$

Here, n = 1

$\lambda=4.53\times10^{-7}\ m$

Hence, The wavelength of light is $4.53\times10^{-7}\ m$

7 0

3 years ago

When 224-nm light falls on a metal, the current through a photoelectric circuit is brought to zero at a stopping voltage of 1.84

OLga [1]

Answer:

3.71 eV

Explanation:

λ = Wavelength of light = 224 nm = 224 x 10⁻⁹ m

c = speed of electromagnetic wave = 3 x 10⁸ m/s

V₀ = stopping potential = 1.84 volts

W₀ = Work function of the metal = ?

Using the equation

$\frac{hc}{\lambda } = eV_{o} + W_{o}$

$\frac{(6.63\times 10^{-34})(3\times 10^{8})}{224\times 10^{-9} } = (1.6\times 10^{-19})(1.84) + W_{o}$

$W_{o}$ = 5.94 x 10⁻¹⁹

$W_{o}$ = 3.71 eV

7 0

3 years ago

Color depends on what characteristic of light?

Andrej [43]

Answer:

On the wavelength

Explanation:

Visible light is just a small portion of the electromagnetic spectrum, which classifies all the electromagnetic waves from shortest wavelength (gamma rays) to longest wavelength (radio waves).

Visible light refers to the part of the spectrum which has wavelength between 380 nm and 750 nm. These are the only electromagnetic wave that our eyes can see, and depending on their wavelength, they appear as a different color. In particular, each color corresponds to a different range of wavelengths:

Violet: 380-450 nm

Blue: 450-495 nm

Green: 495-570 nm

Yellow: 570-590 nm

Orange: 590-620 nm

Red: 620-750 nm

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2 years ago