In which example is friction the most difficult to overcome? a. static friction between a desk and the floor b. rolling friction between a desk on wheels and the floor c. sliding friction between a desk and the floor once it is moving d. fluid friction between a moving desk and the air

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

How do living things obtain phosphorus

Guard cells control which event? the growth of plants capture of solar energy gas exchange in leaves water absorption in roots