1) A cannonball is fired straight up into the air. Its height, h, in metres, after t seconds can be modelled by the function hm = -4.9t2 + 15t + 0.4. 3) Determine the height of the cannonball after 2 seconds. b) Determine the rate of change of the cannon ball at 15 and at 45. c) How long does it take for the cannon ball to return to the ground? d) How fast is the cannonball travelling when it hits the ground? e) When does the cannonball reach its maximum height