Where do earthquake waves originate from? select one:

What are three reasons why nebulae contribute more to stellar formation than other regions of the universe?

statuscvo [17]

Answer:

Nebulae contribute more to stellar formation than other regions because:

Explanation:

A.They have an unlimited supply of hydrogen.

B. They are believed to be rich in hydrogen and helium.

C. They have a three strong gravitational pull.

This are the reasons that Nebulae contribute more to stellar formation than other regions.

5 0

3 years ago

With the switch open, roughly what must be the resistance of the resistor on the right for the current out of the battery to be

jeyben [28]

Question:

Assumptions

Voltage of battery = 24 V

Resistance on the right,20Ω parallel to 10 Ω resistor

Answer:

For the current out of the battery to be the same as when the switch was opened with the switch closed, the resistance on the resistor on the right must be approximately 20/3 Ω

Explanation:

We note that the switch in the assumption is on the same line as the 20 Ω resistor.

With a voltage of 24 V, and the switch closed, we have;

Total resistance = $\frac{1}{\frac{1}{10} +\frac{1}{20} } = \frac{20}{3} \Omega$

Current out of voltage, I = Voltage/(total resistance)

= 24 ÷ 20/3 = 24 × 3/20 = 18/5 A

Therefore, with the switch opened, we get

Resistance on the right = Initial total resistance $= \frac{20}{3} \Omega$

Therefore, with the switch opened, the resistance on the resistor on the right must be approximately equal to the resultant resistance of the two resistances in parallel.

6 0

3 years ago

Consider a heat engine that inputs 10 kJ of heat and outputs 5 kJ of work. What are the signs on the total heat transfer and tot

Oksi-84 [34.3K]

Answer:

Total heat transfer is positive

Total work transfer is positive

Explanation:

The first law of thermodynamics states that when a system interacts with its surrounding, the amount of energy gained by the system must be equal to the amount of energy lost by the surrounding. In a closed system, exchange of energy with the surrounding can be done through heat and work transfer.

Heat transfer to a system is positive and that transferred from the system is negative.

Also, work done by a system is positive while the work done on the system is negative.

Therefore, from the question, since the heat engine inputs 10kJ of heat, then heat is being transferred to the system. Hence, the sign of the total heat transfer is positive (+ve)

Also, since the heat engine outputs 5kJ of work, it implies that work is being done by the system. Hence the sign of the total work transfer is also positive (+ve).

5 0

3 years ago

Why is the efficiency of a machine always less than 100%?

never [62]

Answer:The percentage of the work input that becomes work output is the efficiency of a machine. Because there is always some friction, the efficiency of any machine is always less than 100 percent.

Explanation:

Sub to rockingcoolstyle15 on yt

8 0

3 years ago

What must be true of a force that causes an object to move in a circular motion?

AlladinOne [14]

Before going to answer this question, first we have to understand centripetal force.

The centripetal force is the force which is required to keep the body along its circular path.The direction of the force is along the radius and towards the centre.

$Mathematically\ centripetal\ force\ F_{c} =\frac{mv^2}{r}$

Here m is the mass of the body,v is the velocity of the body and r is the radius of the circular path.

When a body moves in a circular path,its velocity at any point is the tangent drawn at that point.

As centripetal force acts along the radius, it must be perpendicular to the velocity of the body.

Hence the correct answer to the question is- It acts perpendicular to the velocity and is directed toward the center of the circle.

7 0

3 years ago

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