4. A man skis off the edge of a mountain, free-falls for several seconds, and then opens a parachute. The height, h, in metres, of the stuntman above the ground t seconds after leaving the edge of the mountain is given by the following two functions: h(t) =- 4. 9t" + 2015, which represents the height of the stuntman before he opens the parachute. h(t) =- 10.5t + 980, which represents the height of the stuntman after he opens the parachute. a) How many seconds does the man free-fall before opening his parachute? (2 marks) b) What height was the man at when he opened the parachute? (2 marks) c) Verify your solutions. (1 mark)