2. In this question the unit vector i is horizontal and the unit vector j is vertically upwards. All forces are in newtons. A small, heavy box is suspended in mid-air and is held in equilibrium by the tension in a light inextensible string and a horizontal force, as shown in the diagram. tension horizontal force weight The tension in the string is T1, where T1 = 30i + 49j. The horizontal force is F1, where F1 2 pi. (i) Write down the value of p and show that the mass of the box is 5 kg. [2] (ii) Calculate the magnitude of T1 and the angle that T1 makes with the horizontal. [3] Another force F; = 48i 87} is now applied to the box. The force F1 still acts and the box is still in equilibrium. (iii) The new tension in the string is T2 = ai + bj. Calculate the values of a and b. [3]