An insulator is a material that provides resistance to the flow of electric current. Insulators include rubber, plastic, glass since they do not allow electricity to flow through them.
The answer is B. On a sunny day, the air over a lake will be cooler than the air over the bordering land.
This instrument is called a spring scale.
Answer: See explanation
Explanation:
The evolutionary stages for the formation of planets from earliest to latest will be:
1. Dust keeps matter inside the disk cool enough for planet formation to start
2. Dust grains form condensation nuclei on which surrounding atoms condense to form small clumps of matter.
3. Small clumps of matter stick together via the process of accretion to form planetesimals a few hundred kilometers in diameter.
4. Planetesimals begin to accrete, forming protoplanets.
5. A collection of a few planet-sized protoplanets remain in a fairly cleared out disk around the star
Answer:
The average speed can be calculated as the quotient between the distance travelled and the time needed to travel that distance.
To go to the school, he travels 2.4 km in 0.6 hours, then here the average speed is:
s = (2.4km)/(0.6 hours) = 4 km/h
To return to his home, he travels 2.4km again, this time in only 0.4 hours, then here the average speed is:
s' = (2.4 km)/(0.4 hours) = 6 km/h.
Now, if we want the total average speed (of going and returning) we have that the total distance traveled is two times the distance between his home and school, and the total time is 0.6 hours plus 0.4 hours, then the average speed is:
S = (2*2.4 km)/(0.6 hours + 0.4 hours)
S = (4.8km)/(1 h) = 4.8 km/h
