State what is meant by simple harmonic motion.

1. (a)State what is meant by simple harmonic motion.[2]
2. (b)A trolley of mass m is held on a horizontal surface by means of two springs. One spring is attached to a fixed point P. The other spring is connected to an oscillator, as shown in [Figure 3.1]. The springs, each having spring constant k of 130 N m^–1, are always extended. The oscillator is switched off. The trolley is displaced along the line of the springs and then released. The resulting oscillations of the trolley are simple harmonic. The acceleration a of the trolley is given by the expression a = –(2k/m)x where x is the displacement of the trolley from its equilibrium position. The mass of the trolley is 840 g. Calculate the frequency f of oscillation of the trolley. f = .............................................................. Hz [3][3]
3. (c)The oscillator in (b) is switched on. The frequency of oscillation of the oscillator is varied, keeping its amplitude of oscillation constant. The amplitude of oscillation of the trolley is seen to vary. The amplitude is a maximum at the frequency calculated in (b).
4. (c)(i)State the name of the effect giving rise to this maximum.[1]
5. (c)(ii)At any given frequency, the amplitude of oscillation of the trolley is constant. Explain how this indicates that there are resistive forces opposing the motion of the trolley.[2]

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