A fighter plane enters inside the enemy territory, at time 𝑡 = 0 with velocity 𝑣0 = 250 ms−1 and moves horizontally with constant acceleration 𝑎 = 20ms −2 (see figure). An enemy tank at the border, spot the plane and fire shots at an angle θ = 60° with the horizontal and with velocity 𝑢 = 600 ms −1 . At what altitude 𝐻 of the plane it can be hit by the shot?