Mechanical waves V1. The equation for a transverse wave along a string can be written in SI units as y = 0.4sin(3x - 4t + phi) . a) Specify the amplitude, frequency, wavelength and propagation speed of the wave. Also indicate the direction of movement of the wave. b) If the string has a mass of 200 g per meter, with what force is the string tensioned ? c) Determine the phase angle ($) so that a particle in the position x = 0 at t = 0 is in the equilibrium position (y = 0) and is moving upwards (dy/dt>0). $ must be specified in radians and selected in the interval 0 <= phi < 2pi