solve please

(m s) 25 Particle P Particle Q 20 - 1(S) The diagram shows the velocity-time graphs for the motion of two particles P and Q. which travel in the same direction along a straight line. P and Q both start at the same point X on the line, but @ starts to move 7's later than P. Each particle moves with speed 2.5 ms"' for the first 20s of its motion. The speed of each particle changes instantaneously to 4 ms"after it has been moving for 20 s and the particle continues at this speed. (i) Make a rough copy of the diagram and shade the region whose area represents the displacement of P from X at the instant when @ starts. [1] It is given that P has travelled 70 m at the instant when @ starts. (ii) Find the value of T. [21 (iii) Find the distance between P and Q when Q's speed reaches 4 ms . 121 (iv) Sketch a single diagram showing the displacement-time graphs for both P and Q. with values shown on the r-axis at which the speed of either particle changes. [21