For Question c. ii. why does the graph look like what it is on the mark scheme? I get the other parts, except for this c. ii part.

It would be appreciated if you could explain this to me! Thank you.

This question is in two parts. Part 1 is about wave motion. Part 2 is about renewable energy sources. Part 1 Wave motion The diagram shows a wave that is travelling to the right along a stretched string at a particular instant. The dotted line shows the position of the stretched string when it is undisturbed. P is a small marker attached to the string. a. On the diagram above, identify [2] (i) with an arrow, the direction of movement of marker P at the instant in time shown. (ii) the wavelength of the wave. b. The wavelength of the wave is 25mm and its speed is 18mms-. [2] (i) Calculate the time period 7 of the oscillation of the wave. (ii) On the diagram above, draw the displacement of the string at a time : later than that shown in the diagram. C. Marker P undergoes simple harmonic motion. The amplitude of the wave is 1.7x10-2m and the mass of marker P is 3.5x10- [5 3 kg (i) Calculate the maximum kinetic energy of marker P. (ii) Sketch a graph to show how the kinetic energy Ex of marker P varies with time t from t=0 to t=T, where Tis the time period of the oscillation calculated in (b). Annotate the axes of the graph with numerical values. ER 0 10 . t 3T T NNa. (i) downward arrow at P; (ii) clear single wavelength marked; b. (i) frequency:;(Hz)=o.72(Hz); period: (0172 =)1.4s; Award [2] for a bald correct answer. (ii) wave moved to right by one-third of a cycle by eye; - _2_7r. c. (I)w 1.4, G x 3.5 x 10-3 x [ii7:2] x [1.7 x 102?) 2 1.0 x 105J; Award [2] for a bald correct answer. (ii) Ex 1.0x10- J - + + + + + + + O T 3T T + + + + 4 N + + + -+ + + + + correct shape (sin2) ; (allow any phase for this graph) varying between 0 and 1.0x10-5]; { (allow ECF from (c)(i) but do not allow E to be negative) one period takes