A person sitting in the ground floor of a building notices through the window, of height \( 1.5 \mathrm{~m} \), a ball d…

A person sitting in the ground floor of a building notices through the window, of height \( 1.5 \mathrm{~m} \), a ball dropped from the roof of the building crosses the window in \( 0.1 \mathrm{~s} \). What is the velocity of the ball when it is at the topmost point of the window? \( \left(g=10 \mathrm{~m} / \mathrm{s}^{2}\right) \)