>>511274357Not a physicsanon but the cow has much larger mass, it really doesn't want to move even when hit by a train, so when it is eventually forced to move, it's already ripping apart. A human is a lot lighter and could just "ping" off of the train when the force is applied.
A lot of it has to do with how it's hit too. If you've seen the video of the unfortunate donkey standing in a trains path, I think it demonstrates what I said perfectly. Also I failed physics.