A target lies flat on the ground 7 m from the
side of a building that is 10 m tall, as shown
below.
The acceleration of gravity is 10 m/s
2
. Air
resistance is negligible.
A student rolls a 7 kg ball off the horizontal
roof of the building in the direction of the
target. The horizontal speed v with which the ball
must leave the roof if it is to strike the target
is most nearly what? (square roots)