All categories

3 years ago

Match the words in the left-hand column to the appropriate blank in the sentences in the right-hand column.

Physics

1 answer:

zheka24 [161]3 years ago

8 0

Answer:

1. Molecular cloud

2. Close binary

3. Brown dwarf

4. Protostellar wind

5. Thermal pressure

6. Protostellar disk

7. Jet

8. Degeneracy pressure

Explanation:

1. The Sun formed, probably along with other stars, within a large molecular cloud.

2. A Close binary consists of two stars that orbit each other every few days.

3. A Brown dwarf is a "star" so small in mass that its core never gets hot enough to sustain nuclear fusion reactions.

4. Most of the gas remaining from the process of star formation is swept into interstellar space by a protostellar wind.

5. As a protostar's internal temperature increases, its growing thermal pressure helps slow its contraction due to gravity.

6. Planets may form within the protostellar disk that surrounds a forming star.

7. Mass can be lost through a jet of material ejected along a protostar's axis of rotation.

8. A "star" with mass below 0.08 solar mass has its gravitational contraction halted by degeneracy pressure.

You might be interested in

A proton and an electron are released from rest, with only the electrostatic force acting. Which of the following statements mus

lbvjy [14]

Answer:

their electrical potential energy decreases. True, because of the negative sign as the distance decreases, it becomes more negative.

The kinetic energy increases. True, the force is attractive as the distance decreases the force increases, so acceleration and therefore the speed

Explanation:

The only force between the proton and the electron is electric

Fe = k q1q2 / r2

Fe = - k e2 / r2

We can see that it is an attractive force (negative sign)

The electric power energy is

U = k q1 q2 / r

U = -k e2 / r

The kinetic energy is

K = ½ m v2

With the expressions for each term we can analyze the sentences :

Their electric potential energy increases. False,

their electrical potential energy decreases. True, because of the negative sign as the distance decreases, it becomes more negative.

The kinetic energy increases. True, the force is attractive as the distance decreases the force increases, so acceleration and therefore the speed

Kinetic energy decreases False

The acceleration decreases. False, as the force increases so does the acceleration

7 0

3 years ago

Find the voltage across the 15 Ω resistor. . 35 Ω 20 Ω 15 Ω 10 V

almond37 [142]

Answer:

35 Ω

Explanation:

3 0

3 years ago

A Chinook (King) salmon (Genus Oncorynchus) can jump out of water with a speed of 6.75 m / s . If the salmon is in a stream with

Pepsi [2]

Answer:

The maximum height that the fish can jump is 2.19 m.

Explanation:

Hi there!

Please, see the attached figure for a better understanding of the problem.

The motion of the salmon is a parabolic one because when it jumps, it already has a horizontal velocity (see figure).

The position and velocity vectors of the salmon at a time t, can be calculated as follows:

r = (x0 + v0x · t, y0 + v0y · t + 1/2 · g · t²)

v = (v0x, v0y + g · t)

Where:

r = position of the salmon at time t.

x0 = initial horizotal position.

v0x = initial horizontal velocity.

t = time.

y0 = initial vertical position.

v0y = initial vertical velocity.

g = acceleration of gravity.

Looking at the figure, notice that at the maximum height, the vertical velocity is zero (because the velocity vector is horizontal). Using the equation of the vertical component of the velocity, we can obtain the time at which the salmon is at its maximum height:

vy = v0y + g · t

To find the initial vertical velocity, v0y, let´s look at the figure. Notice that the initial velocity is the hypotenuse of the triangle formed with the horizontal velocity and the vertical velocity. Then:

v0² = v0x² + v0y²

Solving for v0y:

v0y = √(v0² - v0x²)

v0y = √((6.75 m/s)² - (1.65 m/s)²)

v0y = 6.55 m/s

Now, using the equation of the vertical component of the velocity at the maximum height (vy = 0):

vy = v0y + g · t

0 = 6.55 m/s + (-9.8 m/s²) · t

-6.55 m/s / -9.8 m/s² = t

t = 0.67 s

Now, using the equation of the vertical position at t = 0.67 s, we can find the maximum height:

y = y0 + v0y · t + 1/2 · g · t²

y = 0 m + 6.55 m/s · 0.67 s + 1/2 · (-9.8 m/s²) · (0.67 s)²

y = 2.19 m

The maximum height that the fish can jump is 2.19 m.

4 0

3 years ago

Consider heat transfer between two identical hot solid bodies and the air surrounding them. The first solid is being cooled by a

Nitella [24]

Answer:

The solution to the question above is explained below:

Explanation:

For which solid is the lumped system analysis more likely to be applicable?

Answer

The lumped system analysis is more likely to be applicable for the body cooled naturally.

Question :Why?

Answer

Biot number is proportional to the convection heat transfer coefficient, and it is proportional to the air velocity. When Biot no is less than 0.1 in the case of natural convection, then lumped analysis can be applied.

Further explanations:

Heat is a form of energy.

Heat transfer describes the flow of heat across the boundary of a system due to temperature differences and the subsequent temperature distribution and changes. There are three different ways the heat can transfer: conduction, convection, or radiation.

Heat transfer analysis which utilizes this idealization is known as the lumped system analysis.

The Biot number is a criterion dimensionless quantity used in heat transfer calculations which gives a direct indication of the relative importance of conduction and convection in determining the temperature history of a body being heated or cooled by convection at its surface. In heat transfer analysis, some bodies are observed to behave like a "lump" whose entire body temperature remains essentially uniform at all times during a heat transfer process.

Conduction is the transfer of energy in the form of heat or electricity from one atom to another within an object and conduction of heat occurs when molecules increase in temperature.

Convection is a transfer of heat by the movement of a fluid. Convection occurs within liquids and gases between areas of different temperature.

7 0

3 years ago

Which best explains why people see carrots as orange

Andru [333]

Beta Carotene is the reason why a carrot is orange. Carotene is a color pigment that is found in large quantities in carrots and it has health benefits as well. The main health benefit of carotene is that our body converts it into vitamin A which is essential.

8 0

4 years ago

Read 2 more answers