Example acceleration profiles for a 1 kg, 10 cm diameter projectile impacting glass beads at three different gravity levels when Fr = 6.3. The acceleration data is normalized by gravity g, and the timeparameter t is normalized by g and the projectile diameter D. Plot (a) gives the acceleration profiles when the data is filtered in the time domain t, and plot (b) gives the profiles when the data is filtered in the normalized time domain t^* where .