All categories

2 years ago

Which is likely to be more common in our Galaxy: white dwarfs or black holes? Why?

Physics

1 answer:

Nookie1986 [14]2 years ago

4 0

Answer:

White dwarfs are likely to be much more common. The number of stars decreases with increasing mass, and only the most massive stars are likely to complete their lives as black holes. There are many more stars of the masses appropriate for evolution to a white dwarf.

You might be interested in

Part a consider a bird that flies at an average speed of 10.7 m/s and releases energy from its body fat reserves at an average r

Alex787 [66]

<span>436 km The conversion factor between kilocalorie/hour and watts is 1.163 (1 kcal/hr = 1.163 watt). So let's convert the energy consumption of the bird from watts to kcal/hr 3.7 w / 1.163 w hr/kcal = 3.18 kcal /hr 1 gram of fat has 9 kcal, so the total number of kcals consumed will be 4 * 9 = 36. So the bird can fly for 36/3.18 = 11.32 hours The distance traveled will be 11.32 h * 3600 s/h * 10.7 m/s / 1000 m/km = 436 km</span>

5 0

3 years ago

Many industries are powered via distant power stations. Calculate the current flowing through a 7,300m long 10. copper power lin

Oliga [24]

Answer:

Current, I = 1000 A

Explanation:

It is given that,

Length of the copper wire, l = 7300 m

Resistance of copper line, R = 10 ohms

Magnetic field, B = 0.1 T

$\mu_o=4\pi \times 10^{-7}\ T-m/A$

Resistivity, $\rho=1.72\times 10^{-8}\ \Omega-m$

We need to find the current flowing the copper wire. Firstly, we need to find the radius of he power line using physical dimensions as :

$R=\rho \dfrac{l}{A}$

$R=\rho \dfrac{l}{\pi r^2}$

$r=\sqrt{\dfrac{\rho l}{R\pi}}$

$r=\sqrt{\dfrac{1.72\times 10^{-8}\times 7300}{10\pi}}$

r = 0.00199 m

$r=1.99\times 10^{-3}\ m=2\times 10^{-3}\ m$

The magnetic field on a current carrying wire is given by :

$B=\dfrac{\mu_o I}{2\pi r}$

$I=\dfrac{2\pi rB}{\mu_o}$

$I=\dfrac{2\pi \times 0.1\times 2\times 10^{-3}}{4\pi \times 10^{-7}}$

I = 1000 A

So, the current of 1000 A is flowing through the copper wire. Hence, this is the required solution.

4 0

2 years ago

To win the game, a place kicker must kick a

Dafna11 [192]

Answer:

1.86 m

Explanation:

First, find the time it takes to travel the horizontal distance. Given:

Δx = 52 m

v₀ = 26 m/s cos 31.5° ≈ 22.2 m/s

a = 0 m/s²

Find: t

Δx = v₀ t + ½ at²

52 m = (22.2 m/s) t + ½ (0 m/s²) t²

t = 2.35 s

Next, find the vertical displacement. Given:

v₀ = 26 m/s sin 31.5° ≈ 13.6 m/s

a = -9.8 m/s²

t = 2.35 s

Find: Δy

Δy = v₀ t + ½ at²

Δy = (13.6 m/s) (2.35 s) + ½ (-9.8 m/s²) (2.35 s)²

Δy = 4.91 m

The distance between the ball and the crossbar is:

4.91 m − 3.05 m = 1.86 m

5 0

3 years ago

The resistance of a wire is not dependent on

Komok [63]

d. Current

It is opposing

3 0

3 years ago

A swimming duck paddles the water with its feet once per time interval of 2.0 s, producing surface waves with this period. The d

vfiekz [6]

Answer:

Part A: What is the duck's speed? v=0.2m/s

Part B: How far apart are the crests behind the duck = 1m

Explanation:

The concept applied here is the DOPPLER EFFECT, for example, if one is driving towards a station at 120km/hr, a higher frequency will be heard. and if you are driving away from the station at the same speed, one will hear a much more lower frequency. Tthese effect was proposed by the Austrian physicist by name Johann Christian doppler.

The detailed steps and appropriate formula is as shown in the attached file.

3 0

2 years ago