A ball is to be shot from level ground with a certain speed. Figure 4-47 shows the range R it will have versus the launch angle ?0. The value of ?0 determines the flight time; let tmax represent the maximum flight time. What is the least speed the ball will have during its flight if ?0 is chosen such that the flight time is 0.630tmax?
Figure: http://edugen.wiley.com/edugen/courses/crs4957/art/qb/qu/c04/fig04_47.gif
Figure: http://edugen.wiley.com/edugen/courses/crs4957/art/qb/qu/c04/fig04_47.gif