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3 years ago

14

When a red giant dies, before it becomes a WHITE DWARF (small, dim, hot star) that eventually becomes a BLACK DWARF (remnant, da

rk, cold matter), it explodes into what?

1 answer:

vagabundo [1.1K]3 years ago

6 0

some massive black dwarfs may eventually produce <u>supernova explosions. </u>These will occur if pycnonuclear (density-based) fusion processes much of the star to iron, which would lower the Chandrasekhar limit for some black dwarfs below their actual mass.

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A woman at an airport is towing her 20.0-kg suitcase at constant speed by pulling on a strap at an angle θ above the horizontal.

Elza [17]

Answer:

Normal force: 167.48 N

Explanation:

First of all it is necessary to draw the free body diagram of the suitcase adding alll the forces stated on the question: the normal force, the friction force and pull force exterted by the woman. Additionally, we need to add the weight, the forces exerted by Earth's gravity. I attached the diagram so you can check it.
We need to resolve all the unknown quantities on this exercise, so we need to write down the sum of forces equations on X-Axis and Y-axis. Remember that force exerted by the woman has an angle with respect the horizontal (X-Axis), that is to say it has force compoents on both X and Y axis. The equations will be equal to zero since the suitcase is at constant speed (acceleration is zero).

∑ $F_{x}$ : $F{x}-20 = 0$

∑ $F_{y}$ : $N -W+F_{y}=0$

Our objetive is to find the value of the normal force. It means we can solve the sum of Y-axis for N. The solution would be following:

$N = W - Fy$

Keep in mind Weight of the suitcase (W) is equal to the suitcase mass times the acceleration caused by gravity (9.81 $\frac{m}{s^{2}}$ . Furthermore, Fy can be replaced using trigonometry as $Fsin(\theta)$ where θ is the angle above the horizontal. So the formula can be written in this way:

$N = mg -Fsin(\theta)$

We need to find the value of θ so we can find the value of N. We can find it out solving the sum of forces on X-axis replacing <em>Fx</em> for Fcos(θ). The equation will be like this:

$Fcos(\theta) -20 = 0$ ⇒ $Fcos(\theta) = 20$ $\theta [tex]\theta=cos^{-1}(20/F)$

Replacing the value of F we will see θ has a value of 55.15°. Now we can use this angle to find the value of N. Replacing mass, the gravity acceleration and the angle by their respective values, we will have the following:

$N = 20 x 9.81 - 35sin(55.15)$ ⇒ $N = 167.48 N$

7 0

3 years ago

1. Meiosis produces daughter cells that are

Marina86 [1]

Answer:

1. A Haploid

2. A. Somatic Cell production

3. B. Gametic cell production

4. C. Mitosis produces identical cells to parent cells.

5. B 4:0

6. C Both parent bees are heterozygous Ll

7. D DNA is made up of chromosomes

8. B Each hypothesis was tested and DNA supported the data better

9. D There may be an increase in pest populations that are resistant to control measures.

10. A They are proven to cause cancer.

11. B a form of a gene

Explanation:

Answer was too long, so is attached in a word document

5 0

3 years ago

A 0.22-caliber handgun fires a 27-g bullet at a velocity of 755 m/s. is the wave nature of matter significant for bullets?

Neporo4naja [7]

<span>All matter can exhibit wave-like behavior, but the question asks if it is significant. A bullet is a very, very large object compared to the light wave-particles where the wave nature is typically observed. So for an object of this magnitude, it is insignificant.</span>

6 0

3 years ago

A velocity vs. time graph starts at 0 and ends at 10 m/s, stretching over a time- span of 15 s with constant acceleration. What

Alex777 [14]

Answer:

75m

Explanation:

6 0

3 years ago

There is strong evidence that Europa, a satellite of Jupiter, has a liquid ocean beneath its icy surface. Many scientists think

dangina [55]

Answer:

4.44 rpm

Explanation:

$\omega$ = Angular speed

G = Gravitational constant = 6.67 × 10⁻¹¹ m³/kgs²

r = Radius of Europa = $\frac{3138000}{2}\ m$

R = Radius of arm = 6 m

The acceleration due to gravity is given by

$g=\frac{GM}{r^2}\\\Rightarrow g=\frac{6.67\times 10^{-11}\times 4.8\times 10^{22}}{\left(\frac{3138000}{2}\right)^2}\\\Rightarrow g=1.3\ m/s^2$

Here the centripetal acceleration of the arm and acceleration due to gravity are equal

$a_c=\omega^2R$

$a_c=g\\\Rightarrow \omega^2R=1.3\\\Rightarrow \omega^2\times 6=1.3\\\Rightarrow \omega=\sqrt{\frac{1.3}{6}}\\\Rightarrow \omega=0.46547\ rad/s$

Converting to rpm

$1\ rad/s=\frac{60}{2\pi}\ rpm$

$0.46547\ rad/s=0.46547\times \frac{60}{2\pi}\ rpm=4.44\ rpm$

The angular speed of the arm is 4.44 rpm

8 0

2 years ago