A penny dropped from the Empire State Building would not kill a person or crack the sidewalk. A penny is too light and has too much air resistance to acquire enough speed to do much damage since it reaches terminal velocity after falling about 15 metres (50 ft). Heavier or more aerodynamic objects could cause significant damage if dropped from that height. https://en.wikipedia.org/wiki/List_of_common_misconceptions_about_science,_technology,_and_mathematics#Physics