1. The problem statement, all variables and given/known data Question: A cannon shoots a ball at angle Ø above the horizontal ground. Neglecting air resistance, and letting r(t) denote the ball's distance from the cannon, What is the largest possible value of Ø if r(t) is to increase throughout the ball's flight? [hint: Write down r2 as x2 + y2, and then find the condition that r2 is always increasing.] 2. Relevant equations r(t) = gt2/2 + v0t + x0 r2 = x2 + y2 x = rcosØ y = rsinØ 3. The attempt at a solution r2 = (gt2/2 + v0t + x0)(gt2/2 + v0t + x0) = x20 + 2x0v0t + x0gt2 + v20t2 + v0gt3 + g2t4/4 = x2 + y2 = r2(cos2Ø + sin2Ø) I don't know how to solve for Ø, so that r2 is always increasing.