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2 years ago

The nebular theory also predicts that the cloud should heat up as it collapses. what physical law explains why it heats up?

1 answer:

4 0

The physical law that explains that is the law of conservation of energy which states that he energy of an isolated sistem remains constant

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What can be inferred when an atom is electrically charged?

Elena-2011 [213]

When an atom becomes electrically charged the number of electrons or protons stops and they are not equal again. The "extra" electron or proton is not balanced by something inside the atom any longer and it starts attracting itself to othet protons or electrons in other atoms.

<h3>What is atomic structure?</h3>

An atomic structure comprises of positively charged nucleus which is surrounded by negatively charged particles called electron and neutron which is neutral charged.

Unlike charges attract each other while like charges repel each other.

Therefore, When an electron is fully charged, the number of electrons will stop to be unequal again.

Learn more about Atomic charge here.

brainly.com/question/18102056

7 0

2 years ago

In space movies, spacecrafts explode and oxygen is needed for a fire to start. Why is it wrong? What would really happen?

Triss [41]

Answer:

Hey

The reason these "space movies" are wrong is because objects in "space" (not in a "space" craft) can't catch on fire because there is no air in "space".

6 0

3 years ago

A(n)is produced around a wire when an electrical current is in the wire.

Nonamiya [84]

Answer: The correct answer is "magnetic field".

Explanation:

A magnetic field is produced around the current carrying wire.

If you bring compass needle around the current carrying wire then it shows the deflection which indicates that there is a magnetic field around the current carrying wire.

Magnetic fields are the area around the surrounding of magnet in which magnetic force can be experienced.

Therefore, a magnetic field is produced around a wire when an electrical current is in the wire.

5 0

3 years ago

Read 2 more answers

Steam is to be condensed on the shell side of a heat exchanger at 150 oF. Cooling water enters the tubes at 60 oF at a rate of 4

zalisa [80]

Answer:

a. 572Btu/s

b.0.1483Btu/s.R

Explanation:

a.Assume a steady state operation, KE and PE are both neglected and fluids properties are constant.

From table A-3E, the specific heat of water is $c_p=1.0\ Btu/lbm.F$ , and the steam properties as, A-4E:

$h_{fg}=1007.8Btu/lbm, s_{fg}=1.6529Btu/lbm.R$

Using the energy balance for the system:

$\dot E_{in}-\dot E_{out}=\bigtriangleup \dot E_{sys}=0\\\\\dot E_{in}=\dot E_{out}\\\\\dot Q_{in}+\dot m_{cw}h_1=\dot m_{cw}h_2\\\\\dot Q_{in}=\dot m_{cw}c_p(T_{out}-T_{in})\\\\\dot Q_{in}=44\times 1.0\times (73-60)=572\ Btu/s$

Hence, the rate of heat transfer in the heat exchanger is 572Btu/s

b. Heat gained by the water is equal to the heat lost by the condensing steam.

-The rate of steam condensation is expressed as:

$\dot m_{steam}=\frac{\dot Q}{h_{fg}}\\\\\dot m_{steam}=\frac{572}{1007.8}=0.5676lbm/s$

Entropy generation in the heat exchanger could be defined using the entropy balance on the system:

$\dot S_{in}-\dot S_{out}+\dot S_{gen}=\bigtriangleup \dot S_{sys}\\\\\dot m_1s_1+\dot m_3s_3-\dot m_2s_2-\dot m_4s_4+\dot S_{gen}=0\\\\\dot m_ws_1+\dot m_ss_3-\dot m_ws_2-\dot m_ss_4+\dot S_{gen}=0\\\\\dot S_{gen}=\dot m_w(s_2-s_1)+\dot m_s(s_4-s_3)\\\\\dot S_{gen}=\dot m c_p \ In(\frac{T_2}{T_1})-\dot m_ss_{fg}\\\\\\\dot S_{gen}=4.4\times 1.0\times \ In( {73+460)/(60+460)}-0.5676\times 1.6529\\\\=0.1483\ Btu/s.R$

Hence,the rate of entropy generation in the heat exchanger. is 0.1483Btu/s.R

4 0

3 years ago

The driver must stop and remain stopped to let a pedestrian cross at a crosswalk when the pedestrian is _____________.

RSB [31]

Answer: the correct option is B ( on the half of the road that the vehicle is traveling).

Explanation: according to Georgia Code About Pedestrians; The driver must stop and remain stopped to let a pedestrian cross at a crosswalk when the pedestrian is

on the half of the road that the vehicle is traveling.

4 0

3 years ago

Read 2 more answers