Ignoring air resistance, both large and small objects fall about 5 meters in the first second.<p>Expressed in terms of their size, however, large objects fall less far. For example, a 100m diameter rock falls just 5% of its diameter in that second, a 1m one falls five times its diameter. That tricks your brain.<p>Also, for the video you show, there is quite a bit of non-falling, with the rock sliding down/tilting. Rolling down a hill is harder for large objects than for normal size objects (very small objects may roll slower again both because of relatively larger air resistance and because the slope may be rougher at smaller scale)