A firefighter carries a hose up a ladder to a height of 10.0 m,
so that she can spray water onto a burning roof that is 9.00 m
high. She holds the hose horizontally, and sees that the water
strikes the roof 7.0 m in front of her position (i.e. horizontal
component of displacement is 7.0 m). The hose is connected to a
very large, pressurized chamber in the fire truck, which is sitting
at ground level. What is the...