If you were trying to build a soundproof room, which of the following materials would you choose in order to absorb the most sound, based on the coefficient of absorption for each material? a. carpet b. wood c. heavy curtains d. concrete

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