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3 years ago

8

Once all the hydrogen is gone, the star starts to collapse. if it collapses enough, what fuel will now be used? what color will

it burn?

1 answer:

romanna [79]3 years ago

7 0

It will burn helium and turn dark orange. Eventually, it is all iron and cannot burn that, so it becomes dark. Hope this helps!!!

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A fixed mass of gas has a volume of 25 cm³. The pressure of the gas is 100 kPa.

tekilochka [14]

Answer:

67 kPa

Explanation:

Given that,

Initial volume, V₁ = 25 cm³

Initial pressure, P₁ = 100 kPa

Final volume, V₂ = 15 cm³

We need to find the change in pressure of the gas. The relation between the volume and pressure of a gas is given by :

$P\propto \dfrac{1}{V}\\\\\dfrac{P_1}{P_2}=\dfrac{V_2}{V_1}\\\\P_2=\dfrac{P_1V_1}{V_2}\\\\P_2=\dfrac{100\times 25}{15}\\\\=166.66\ kPa$

or

= 167 kPa

The change in pressure,

= P₂ - P₁

= 167 kPa - 100 kPa

= 67 kPa

Hence, the correct option is (a).

7 0

3 years ago

The pendulum consists of two slender rods AB and OC which each have a mass of 3 kg/m. The thin plate has a mass of 10 kg/m2. Det

MatroZZZ [7]

Answer:

the answer is below

Explanation:

The diagram of the problem is given in the image attached.

Mass of rod AB = (0.4 m + 0.4 m) * 3 kg/m = 2.4 kg

Mass of rod OC = (1.5 m) * 3 kg/m = 4.5 kg

Mass of plate = 10 kg/m²[ (π* 0.3²) - (π* 0.1²)] = 2.513 kg

The center of mass is:

$\hat{y}[2.4+2.513+4.5]=(0.75*4.5)+(2.513*0.5)\\\\\hat{y}=0.839\\\\I_{AB}=\frac{1}{12}*2.4*(0.4+0.4)^2= 0.128\ kg/m^2\\\\I_{OC}=\frac{1}{12}*4.5*(1.5)^2= 3.375\ kg/m^2\\\\I_{Gplate}=\frac{1}{2}*(\pi*0.3^2*10)*(0.3)^2-\frac{1}{2}*(\pi*0.1^2*10)*(0.1)^2= 0.126\ kg/m^2\\\\I_{plate}=I_{Gplate}+md^2=0.126+2.513(1.8^2)=8.27\ kg/m^2\\\\I_o=I_{plate}+I_{AB}+I_{OC}\\\\I_{o}=0.128+3.375+8.27=11.773\ kg/m^2 \\\\I_G=I_o-m_{tot}\hat{y}^2\\\\I_G=11.773-(9.413*0.839^2)\\\\I_G=5.147\ kg/m^2$

4 0

3 years ago

Newton's law of cooling is , where is the temperature of an object, is in hours, is a constant ambient temperature, and is a pos

kirill [66]

Complete Question

The complete question is shown on the first uploaded image

Answer:

The time taken is $t = 6.89 \ hrs$

Explanation:

From the question we are told that

The value of $k = 0.15hr^{-1}$

The the interior temperature is $u(t = 0) = 70 ^oF$

The external temperature is $T = 11 ^oF$

The required interior temperature is $u_{t} = 32 ^oF$

The newton cooling law is

$\frac{du}{dt} = -k (u -T)$

=> $\frac{du}{u-T} = - kdt$

Now integrate both sides we have

$\int\limits \frac{du}{u-T} =\int\limits - kdt$

$ln (u - T) = -kt + c$

Since c is a constant lnC = c will also give a constant so

$ln (u - T) = -kt + ln C$

=> $\frac{(u -T)}{C} = e^{-kt}$

=> $u = T + Ce^{-kt}$

substituting value

$70 = 11 +Ce^{-0* 0.15}$

$C = 59$

Hence

$u_t = 11 + 59 e^{-0.15 *t}$

$32= 11 + 59 e^{-0.15 *t}$

=> $t = -\frac{ln(\frac{21}{59} )}{0.15}$

$t = 6.89 \ hrs$

3 0

3 years ago

A car is traveling at 96km/hr. what is the acceleration of a car traveling a distance of 100m and come to rest?

8090 [49]

Answer:

Explanation:

v² = u² + 2as

v = 0

u = 96 / 3.6 = 26.7 m/s

0² = 26.7² + 2a100

a = -3.5555555... ≈ -3.6 m/s²

the negative sign indicated the acceleration vector opposes the (assumed positive) initial velocity vector direction.

6 0

3 years ago

An astronomer would most likely use the doppler effect to question 12 options: 1) measure the color of a star. 2) measure the pa

zalisa [80]

The answer would be number four. I'm sorry if I am too late. Byes.....

6 0

3 years ago

Read 2 more answers