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What is CO (Carbon Omission)

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שאלה #133775

		Is not dangerous as it is everywhere
done		Blocks the oxygen from reaching the brain
		is not more dangerous than CO2
		Is related to global warming

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מיין לפי דירוג חדש ישן

Particle motion is affected by

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שאלה #133777

		The drag force
		The size of the particle
		The viscosity of the particle
done		All of the above

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מיין לפי דירוג חדש ישן

The drag force is

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שאלה #133779

		Depends on the viscosity of the particle
done		Depends on the viscosity of the fluid
		epends on particle color
		Does not depend on particle density

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מיין לפי דירוג חדש ישן

The characteristic time τ means

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שאלה #133782

done		Is mainly a function of particle size
		Reflects the reaction time for changes in flow velocity
		Is very small for large particles
		Does not depend on fluid viscosity

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מיין לפי דירוג חדש ישן

According to the exercise solved in the video presentation, at t=τ

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שאלה #133783

		The particle velocity decreased from 1 m/s to 0.37 m/s
		If the initial velocity was 10 m/s it would reduce to 3.7 m/s
		If it was τ/2, it would have been 0.61 m/s
done		All of the above

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מיין לפי דירוג חדש ישן

Increasing the emitted particle size:

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שאלה #133784

		Increases the risk associated with the particle
		Increases its time in the air
done		Reduces the probability of it penetrating deep into the lungs
		ncreases the difficulty of capturing it

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מיין לפי דירוג חדש ישן

Nanoscale particles ....

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שאלה #133785

done		Can reach the brain
		Do not constitute any risk at all
		Cannot attach to the surface of the respiratory system
		Are not formed from engines

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מיין לפי דירוג חדש ישן

Grouping of smoke particles may..

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שאלה #133786

		May lead to their coagulation
		May reduce the number of particles
		May enable better filtration and reduce air pollution
done		All of the above

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מיין לפי דירוג חדש ישן

The effects of air pollution can be reduced if

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שאלה #133787

done		Fewer smoke particles are emitted
		More NO2 is emitted from combustion
		e decrease emitted particles’ size
		he emitted particles have less mass

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מיין לפי דירוג חדש ישן

We can group and make particles larger, if

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שאלה #133788

		We take advantage of the characteristic time τ
		We induce velocity variation in the vehicle exhaust system
		We design an exhaust system according to a mathematical model
done		All of the above

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מיין לפי דירוג חדש ישן

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