Do heavier animals sustain heavier impacts better or worse?

Question

Suppose I were in a minor accident. I was standing still weighing 50 kg. The vehicle weighed 500kg and was only going at 5 kph...

Would an elephant weighing 5000 kg need to be hit by a 50000 kg weight travelling 5 kph in order to feel what I felt? Or do I need to scale up the speed too?

(Disclaimer: despite my choice of phrasing, no elephants shall be hurt by gigantic weights in the making or answering of this question :P )

Answer 1

I changed my mind since my first answer. The elephant would equally injured in your example. The scaling is that the mass of an animal of a given shape increases with the third power of its height, but the strength of its bones only increases as the square of its height. It's this basic scaling that prevents large animals from being beyond a certain size; beyond this, they couldn't lift there own weight. When it comes to impact with an object from the side, though, the amount of elastic energy their bones can absorb with out breaking increases in proportion to their mass - just as would the impactor in your first example.

Here's how it works. You have a different shape than an elephant (I presume), so an easier example to consider is a 50 kg anteater (say) that has the same proportions as a 5000 kg elephant. To be 100 times heavier, the elephant would then have to be 4.6 times taller (4.6^3=100). The elephant's ribs, though, would only be 21 times stiffer and stronger (4.6^2=21). If an object hit the elephant at the same speed as one that would almost break an anteater's ribs, but was 100 times more massive, the elephant's (21 times stiffer ribs) would bend 4.6 times further in to absorb the 100 times greater kinetic energy. But, since the ribs are also 4.6 times longer, they would be able to bend that far equally well. This assumes the object has the same shape and density so that it would be the same relative size compared to the elephant (say a ball 4.6 times the diameter) and, therefore, impact the same number of ribs.

Answer 2

Would an elephant weighing 5000 kg need to be hit by a 50000 kg weight traveling 5 kph in order to feel what I felt?

I think yes, but not sure. (I don't know how vulnerable are the elephants.)

Or do I need to scale up the speed too?

No.

If you scale up the speed, the energy of the car will increase quadratically. ( E = 0.5 m v^2 )

Answer 3

I'm not up on Vegan requirements but those dog sled racers who do the Iditarod Great Sled Race have a diet very heavy on butter and oat meal. i don't know if Vegans eat butter. Personally I would add a lot of steaks. In 1979/1980 I worked for Getter Trucking which had a terminal in Williston. I rented a basement apartment in someone's house (relative of a friend) since even back then there was a housing shortage due to the oil boom. We worked 6 days a week averaging 13.5 hours per day, all winter long, moving oil rigs, delivering pipe, etc. Often we slept out of town, working in Montana, staying in some motel which, being old Norwegian converted, it was like an Amish room. But somewhere in whatever little town we got van'ed to at the end of the day, the bar/restaurant was open late. That was a very cool experience. The cafe was closed and little kids were playing cards on the tables but if one went through the curtain there was the bar which shared the same kitchen with the cafe. Dogs and kids ran through the isle, one could hear Norwegian being spoken by old farmers in the next booth. Couple of drinks, a hot meal and then to the motel. On the days when I got "home" I would fry up a steak on the stove and crash. The only things open on Sundays were the book store in the basement of the closed drug store and the laundromat. Later on they put in a 7-11 convenience store but it was not 24 hours. 7 to 11. I guess a Vegan would have to devote the time to cooking up rice and beans plus some other stuff to fill in the amino acids which rice and beans do not contain. i don't suppose Vegans can use lard? That would be a good source of animal fat. Not up on Veganism, does butter have a face? Can they eat butter?

Answer 4

the impact of the force that you feel will depend on the mass of what hit you. F=MA

so yeah i guess for the elephant to feel what you felt, a heavier vehicle should hit it.

the acceleration also plays a role. if a fast moving fat vehicle hits you, you'll probably be more hurt than if a huge vehicle moving at snail's pace hit the elephant.