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notka56 [123]
3 years ago
6

A heliocentric system is _____-centered.

Physics
2 answers:
KonstantinChe [14]3 years ago
8 0

Answer:

Sun centered

Explanation:

Heliocetric model in the cosmological model of our solar system in which it is believed that star “Sun” lies at the center of system and all other planets including the moon and earth move around sun in circular –elliptical path. This model was widely accepted as the observations related to the climate, seasons, and arrangement of star was easily explained through  this system.

aniked [119]3 years ago
3 0
A heliocentric system is a sun-centered 
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Which source would provide the most reliable information about the safety of nuclear power plants?
soldier1979 [14.2K]

This paper is about the main conventional types of nuclear reactor. For more advanced types, see Advanced Reactors and Small Reactors papers, and also Generation IV reactors.

A nuclear reactor produces and controls the release of energy from splitting the atoms of certain elements. In a nuclear power reactor, the energy released is used as heat to make steam to generate electricity. (In a research reactor the main purpose is to utilise the actual neutrons produced in the core. In most naval reactors, steam drives a turbine directly for propulsion.)

The principles for using nuclear power to produce electricity are the same for most types of reactor. The energy released from continuous fission of the atoms of the fuel is harnessed as heat in either a gas or water, and is used to produce steam. The steam is used to drive the turbines which produce electricity (as in most fossil fuel plants).

The world's first nuclear reactors operated naturally in a uranium deposit about two billion years ago. These were in rich uranium orebodies and moderated by percolating rainwater. The 17 known at Oklo in west Africa, each less than 100 kW thermal, together consumed about six tonnes of that uranium. It is assumed that these were not unique worldwide.

Today, reactors derived from designs originally developed for propelling submarines and large naval ships generate about 85% of the world's nuclear electricity. The main design is the pressurised water reactor (PWR) which has water at over 300°C under pressure in its primary cooling/heat transfer circuit, and generates steam in a secondary circuit. The less numerous boiling water reactor (BWR) makes steam in the primary circuit above the reactor core, at similar temperatures and pressure. Both types use water as both coolant and moderator, to slow neutrons. Since water normally boils at 100°C, they have robust steel pressure vessels or tubes to enable the higher operating temperature. (Another type uses heavy water, with deuterium atoms, as moderator. Hence the term ‘light water’ is used to differentiate.)

Components of a nuclear reactor

There are several components common to most types of reactors:

Fuel. Uranium is the basic fuel. Usually pellets of uranium oxide (UO2) are arranged in tubes to form fuel rods. The rods are arranged into fuel assemblies in the reactor core.*
* In a new reactor with new fuel a neutron source is needed to get the reaction going. Usually this is beryllium mixed with polonium, radium or other alpha-emitter. Alpha particles from the decay cause a release of neutrons from the beryllium as it turns to carbon-12. Restarting a reactor with some used fuel may not require this, as there may be enough neutrons to achieve critical when control rods are removed.

Moderator. Material in the core which slows down the neutrons released from fission so that they cause more fission. It is usually water, but may be heavy water or graphite.

Control rods. These are made with neutron-absorbing material such as cadmium, hafnium or boron, and are inserted or withdrawn from the core to control the rate of reaction, or to halt it.*  In some PWR reactors, special control rods are used to enable the core to sustain a low level of power efficiently. (Secondary control systems involve other neutron absorbers, usually boron in the coolant – its concentration can be adjusted over time as the fuel burns up.)
* In fission, most of the neutrons are released promptly, but some are delayed. These are crucial in enabling a chain reacting system (or reactor) to be controllable and to be able to be held precisely critical.

Coolant. A fluid circulating through the core so as to transfer the heat from it.  In light water reactors the water moderator functions also as primary coolant. Except in BWRs, there is secondary coolant circuit where the water becomes steam. (See also later section on primary coolant characteristics)





8 0
3 years ago
Suppose you are driving a car around in a circle of radius 212 ft, at a velocity which has the constant magnitude of 43 ft/s. A
Elanso [62]

To solve this problem we will apply the concepts related to dynamic equilibrium. The vertical component of the tension is equivalent to the centripetal Force while the horizontal component of the tension is equivalent to the weight, therefore we will have the two equations,

Tsin\alpha = \frac{mv^2}{r}

Tcos\alpha = mg

Our values are,

v = 43ft/s = 13.11m/s

r = 212ft = 64.62m

Therefore if we divide both equation we have,

tan \alpha = \frac{v^2}{rg}

Replacing,

tan\alpha = \frac{13.11^2}{(64.62)(9.8)}

tan\alpha = 0.2714

\alpha = tan^{-1} (0.2714)

\alpha = 15.18\°

Therefore the angle required is 15.18°

6 0
3 years ago
A horizontal force of 50 N is required to push a wagon across a sidewalk at a constant speed.
Lerok [7]
The answer is In fact A because it’s unbalanced
5 0
3 years ago
You glide 28 units to the +y-direction with respect to the +x-axis, then move 32 units with respect to the +x-direction. What is
NNADVOKAT [17]

This question can be solved by using Pythagora's Theorem.

The resultant magnitude of the movement is "42.5 units".

The x and y components of the movement are given. We can use Pythagora's Theorem to find the resultant of these movements. Hence, applying the Pythagora's Theorem<em>:</em>

d = \sqrt{d_x^2+d_y^2}

where,

d = resultant movement = ?

d_x = movement in x direction = 32 units

d_y = movement in y direction = 28 units

Therefore,

d = \sqrt{(32\ units)^2+(28\ units)^2}

<u>d = 42.5 units</u>

Learn more about Pythagora's Theorem here:

brainly.com/question/343682?referrer=searchResults

The attached picture shows Pythagora's Theorem<em>.</em>

4 0
2 years ago
What type of tectonic plate boundary exists along the edge of the North American plate near the coast of Northern California, Or
kobusy [5.1K]

Answer:

-transform plate boundary

- false

4 0
3 years ago
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