A small rock is thrown vertically upward with a speed of 23.0 111/ s from the edge of the roof of a 21.0-111-tall building. The rock doesn't hit the building on its way back down and lands in the street below. Ignore air resistance. Part A What is the speed of the rock just before it hits the street? Express your answer with the appropriate units. ? U= Value Units Submit Request AnswerPart B How much time elapses from when the rock is thrown until it hits the street? Express your answer with the appropriate units. LLA t= Value Units Submit Request