You drop a 2.10 kg book to a friend who stands on the ground at distance D = 12.6 m below with outstretched hands at distance d = 1.46 m above the ground. (a) What is the speed of the book when it reaches the hands? m/s (b) If we substituted a second book with twice the mass, what would its speed be? m/s (c) If, instead, the book were thrown down, would the answer to (a) increase, decrease, or remain the same?