Question 4 - 10 marks You should be able to answer this question after studying Unit 2. (a) (i) Write the following quadratic expression in completed square form 23 191 8 [1] (ii) Hence solve the equation 23 =0. 191 191 [2] (iii) Using the strategy described in Section 4.9 of Unit 2 in Book A, or any well-described method, sketch the graph of = s? -to - #. (You should sketch this by hand rather than using any software.) [2] (b) During a tennis match, a player returns a ball towards his opponent, hitting the ball when it is at a height of 1.25 metres above the ground. The vertical displacement h (in metres, measured from the level ground) is modelled by the equation h= = where t 2 0 is the time in seconds since the ball was hit. (i) After 2 seconds the ball arrives at the net, which is 1 metre high at that point. Will the ball travel over the net or hit it? [2] (ii) At what time will the ball be at a height of 1 metre above the ground? Give your solution to 1 decimal place. [3]