actually to get ton miles of kinetic energy you would need to square the 10mph for 100
Or you could need to convert 10 mph into ft per second, before multiplying by itself then by the weight in grains then divide by 450,437 to get ft lb of energy then divide that by an addition 2000 to get ft tons of energy
10mph = 52,800f per hour/3600 seconds per hour or 14.66 fps call it 15fps, 100,000 tonsx2000=200,000,000x7000=1,400,000,000,000gr 15x15=225x14=315,000,000,000,000/450,437=6,993,000,000,000ftlb or
about 3,500,000,000 ft tons of energy
In any event this kind of force is more commonly refereed to as an MEGA THUD
The vibration that went up the pier and along the spans must have been tremendous. Think about hitting something solid with good blow with a 16# sledge hammer and then multiply it by 2 billion times because 1,000,000 tons by 2,000# per ton give you 2 billion and that makes one big hammer