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3 years ago

What is the temperature of a star (in Kelvin) if its peak wavelength is 150 nm (that is, 150 x 10^-9 m)?

Physics

1 answer:

liq [111]3 years ago

7 0

Answer:

19320 K

Explanation:

The temperature of a star is related to its peak wavelength by Wien's displacement law:

$T=\frac{b}{\lambda}$

where

T is the absolute temperature at the star's surface

$b=2.898 \cdot 10^{-3}m\cdot K$ is Wien's displacement constant

$\lambda$ is the peak wavelength

Here we have

$\lambda=150 nm = 150\cdot 10^{-9}nm$

Substituting into the equation, we find

$T=\frac{2.898\cdot 10^{-3}}{150\cdot 10^{-9}}=19320 K$

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What is the mass of an object with a density of 18 g/cm3 and a volume of 25 cm3

DiKsa [7]

Answer: 0.72 grams

Explanation: Mass can be extracted from the formula of density. D=M/V where D is density and V is volume. Therefore:

18 g/cm^3 = M(25 cm^3) --> Divide by 18g/cm^3 by 25 cm^3 to isolate mass. --> 0.72 =M --> Now, to find out which unit you need to use for mass, just look at the density. You can see it is in g/cm^3, and cm^3 was already used for the volume. Thus, gram units are left, so that will be the unit needed, making the final answer 0.72 grams. Hope this helps :)

5 0

2 years ago

A golf ball (m = 59.2 g) is struck a blow that makes an angle of 50.5 ◦ with the horizontal. The drive lands 130 m away on a fla

fomenos

Answer:

The force is calculated as 338.66 N

Explanation:

We know that force is given by

$\overrightarrow{F}=\frac{d\overrightarrow{p}}{dt}=\frac{m(v_{f}-v_{o})}{\Delta t}$

We know that range of a projectile is given by

$R=\frac{v_{o}^{2}sin(2\theta )}{g}$

it is given that R=130 m applying values in the above equation we get

$R=\frac{v_{o}^{2}sin(2\theta )}{g}\\\\v_{0}=\sqrt{\frac{Rg}{sin(2\theta )}}\\\\\therefore v_{o}=\sqrt{\frac{130\times 9.81}{sin(2\times 50.5_{o}} )}\\\\v_{o}=36.04m/s$

Thus the force is obtained as

$\overrightarrow{F}=\frac{d\overrightarrow{p}}{dt}=\frac{59.2\times 10^{}-3(36.04-0)}{6.3\times 10^{-3}}$

Thus force equals $F=338.66N$

4 0

3 years ago

Read 2 more answers

What could you do to increase the electric potential energy between two

SSSSS [86.1K]

Answer:

Increase the charge of one particle by a factor of 16

Explanation:

3 0

2 years ago

Read 2 more answers

Dolphins communicate underwater using sound waves. This is called ________.

Ray Of Light [21]

Answer:

D. echolocation

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7 0

2 years ago

Read 2 more answers

A projectile rolls off a cliff with a velocity of 40 m/s. The cliff is 60 meters high.

masya89 [10]

Answer:

1) t = 3.45 s, 2) x = 138 m, 3) v_{y} = -33.81 m /s, 4) v = 52.37 m / s ,

5) θ = -40.2º

Explanation:

This is a projectile exercise, as they indicate that the projectile rolls down the cliff, it goes with a horizontal speed when leaving the cliff, therefore the speed is v₀ₓ = 40 m / s.

1) Let's calculate the time that Taardaen reaches the bottom, we place the reference system at the bottom of the cliff

y = y₀ + $v_{oy}$ t - ½ g t²

When leaving the cliff the speed is horizontal v_{oy}= 0 and at the bottom of the cliff y = 0

0 = y₀ - ½ g t2

t = √ 2y₀ / g

t = √ (2 60 / 9.8)

t = 3.45 s

2) The horizontal distance traveled

x = v₀ₓ t

x = 40 3.45

x = 138 m

3) The vertical velocity at the point of impact

v_{y} = I go - g t

v_{y} = 0 - 9.8 3.45

v_{y} = -33.81 m /s

the negative sign indicates that the speed is down

4) the resulting velocity at this point

v = √ (vₓ² + v_{y}²)

v = √ (40² + 33.8²)

v = 52.37 m / s

5) angle of impact

tan θ = v_{y} / vx

θ = tan⁻¹ v_{y} / vx

θ = tan⁻¹ (-33.81 / 40)

θ = -40.2º

6) sin (-40.2) = -0.6455

7) tan (-40.2) = -0.845

8) when the projectile falls down the cliff, the horizontal speed remains constant and the vertical speed increases, therefore the resulting speed has a direction given by the angle that is measured clockwise from the x axis

6 0

3 years ago