Aball is dropped from rest at point o (height unknown). after falling for some time, it passes by a window of height 3 m and it does so in 0.49 s. the ball accelerates all the way down; let va be its speed as it passes the window’s top a and vb its speed as it passes the window’s bottom b. o a b 3 m bb b b b b b b b b b b x y how much did the ball speed up as it passed the window; i. e., calculate ∆vdown = vb −va ? the acceleration of gravity is 9.8 m/s 2 . answer in units of m/s. 017 (part 2 of 2) 10.0 points calculate the speed va at which the ball passes the window’s top. answer in units of m/s.