“Why do you want to square v?”
kinetic energy
E = (mv**2)/2
70 mph is just over 102 ft/sec, not 88 ft/sec
bowling ball mass of 15 pounds equates to 0.466 slugs (pounds are a unit of force, not mass)
gives us about 2425 foot-pounds of energy. So the analogy of a BB hitting an auto is not too far off.
Much about a collision result depends on the materials of the colliding objects, their angle of impact, their shape, etc. Momentum is a factor: the scalar product of mass and velocity.
To carry on with the analogy, a human struck by that 15-pound bowling ball traveling 70 mph (102 ft/sec) will sustain injuries quite different from a human struck by - say - a 30 cal bullet traveling 2700 ft/sec (common impact velocity fired from many hunting rifles), though the kinetic energy of the projectiles are nearly identical.
We know from recent news that a train hitting an SUV can derail -- I was surprised to learn that. I have also arrived on a scene where a freight train passed through a semi trailer only minutes before - no derail; I suppose because it was a perfect broadside.
The smell of Kraft jelly and bar-b-cue sauce was heavy in the air, though -- that being the cargo in the trailer.