What are the benefits of cleaning something to a level of cleanliness beyond what is required? what are some possible disadvantages of doing so?

Johnny rode his bike to a friend's house 4 blocks down the street in his neighborhood. he immediately rode back home once he realized his friend was not able to play. what was his displacement for the total bike ride? how did you determine this? what could we use as a reference point to determine he was in motion during his bike ride? why can you use it as a reference point

The energy required to vaporize a certain amount of a substance is greater than the amount of energy necessary to raise the temperature of the same amout of that substance by 1 degreee celcius

Math focus 4. calculate a map has index contours at 250 m, 500 m, and 750 m. what is the contour interval?