In this work a nondimensional formulation of an analytical model was used to study the ballistic behaviour of composite plates made from woven laminates of E-glass fibres. From this model the influence of two nondimensional ratios (the geometry and density ratios) at the ballistic limit, contact time, and energy-absorption mechanisms were analysed at different impact velocities. The increase in both ratios raises the ballistic limit and varies the contact time between the projectile and plate. At impact velocities that do not cause perforation, the contact time decreases while at impact velocities over the ballistic limit, this time increases. Regardless of the ratio, the main energy-absorption mechanism is the fibre failure at velocities below the ballistic limit, and the cone movement for impact velocities over the ballistic limit. At the ballistic limit the main mechanisms are fibre failure and fibre elastic deformation.