קיימות 2024

Discuss, Learn and be Happy דיון בשאלות

• «
• 1
• 2
• 3
• 4
• 5
• 6
• 7
• 8
• ...
• 16
• 17
• »

(is? does?) CO:

-

1

+

שאלה #133460

		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

• gavel
• mood_bad
• share

הגב

מיין לפי דירוג חדש ישן

Particle motion is affected by:

-

1

+

שאלה #133461

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

• gavel
• mood_bad
• share

הגב

מיין לפי דירוג חדש ישן

The drag force:

-

1

+

שאלה #133462

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

• gavel
• mood_bad
• share

הגב

מיין לפי דירוג חדש ישן

The characteristic time τ:

-

1

+

שאלה #133465

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

• gavel
• mood_bad
• share

הגב

מיין לפי דירוג חדש ישן

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

-

1

+

שאלה #133466

		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

• gavel
• mood_bad
• share

הגב

מיין לפי דירוג חדש ישן

Increasing the emitted particle size:

-

1

+

שאלה #133468

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

• gavel
• mood_bad
• share

הגב

מיין לפי דירוג חדש ישן

Nanoscale particles (can?):

-

1

+

שאלה #133470

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

• gavel
• mood_bad
• share

הגב

מיין לפי דירוג חדש ישן

Grouping of smoke particles:

-

1

+

שאלה #133471

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

• gavel
• mood_bad
• share

הגב

מיין לפי דירוג חדש ישן

The effects of air pollution can be reduced if:

-

1

+

שאלה #133473

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

• gavel
• mood_bad
• share

הגב

מיין לפי דירוג חדש ישן

We can group and make particles larger, if:

-

1

+

שאלה #133475

		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

• gavel
• mood_bad
• share

הגב

מיין לפי דירוג חדש ישן

• «
• 1
• 2
• 3
• 4
• 5
• 6
• 7
• 8
• ...
• 16
• 17
• »