Two travelling waves of equal amplitudes and equal frequencies move in opposite directions along a string. They interfere to produce a stationary wave whose equation is given by $y=10\cos \left(\pi x\right)\sin \left(\frac{2\pi t}{T}\right)cm,$ x is in meter and t in second. The amplitude of the particle at $x=\frac{4}{3}m$ will be _____cm.