Ernie is sitting by a bathtub investigating circular waves created by his rubber ducky. ernie takes a series of measurements and finds that the height of the water, with respect to the bottom of the tub, is described by the wavefunction y(r, t)-1m+ (0.1 m) sin ( t _4π1+π/2) the variable r denotes the horizontal distance away from the rubber ducky measured in meters, so r20m and the ducky is at r = 0 m. (i) what are the wavelength λ, time period t and speed of propagation u of the wave? is the wave moving inwards (towards decreasing r) or outwards (towards increasing r)? (ii) plot the vertical displacement of the wave at t 1s for at least two wavelengths. (ii) plot the vertical displacement of the rubber ducky for at least two time periods