Consider mass particle system below and find the magnitude and direction of net gravitational force acts on particle at point C? ABCD is square shape with length of each side a=1.5 m and mass of each particle as follows, $m_1$=2.5 kg, $m_2$=3.8 kg, $m_3$=6.2 kg, $m_4$=1.8 kg. Universal Gravitational Constant, G= 6.67*10$^{-11}$ Nm$^2$/kg$^2$.