Kinetic energy, size of object, and force applied

[Skeet_man]

Kinda looking to confirm what I already suspect.

All things being equal, if two objects have the same kinetic energy, does the fact that one is larger and heavier than the other (although at a slower velocity) mean anything?

Specifically when comparing bullets. One bullet .451" in diameter, 230 grains in weight, traveling at 880 feet per second. Second bullet .356" in diameter, 124 grains in weight, traveling 1200fps. Both bullets have 396 ft/lb of kinetic energy. However, in a somewhat ad-hoc comparison against targets, the larger slower bullet is ostensibly being shown to impart more force on the target, causing it to tip over, whereas the faster lighter bullet fails to do so.

To my mind, at least in this instance, ft/lb is ft/lb.

 

[NFuller]

All things being equal, if two objects have the same kinetic energy, does the fact that one is larger and heavier than the other (although at a slower velocity) mean anything?

Other than what you have stated, not really.

Specifically when comparing bullets. One bullet .451" in diameter, 230 grains in weight, traveling at 880 feet per second. Second bullet .356" in diameter, 124 grains in weight, traveling 1200fps. Both bullets have 396 ft/lb of kinetic energy. However, in a somewhat ad-hoc comparison against targets, the larger slower bullet is ostensibly being shown to impart more force on the target, causing it to tip over, whereas the faster lighter bullet fails to do so.

Just for reference, a ft/lb is not a unit of energy by a ft*lb is. To answer your question, the faster bullet may just go through the target before it can transfer all of its energy to the target.

 

[A.T.]

However, in a somewhat ad-hoc comparison against targets, the larger slower bullet is ostensibly being shown to impart more force on the target, causing it to tip over, whereas the faster lighter bullet fails to do so.

The heavier slower bullet has more momentum, if kinetic energies are the same.

Assuming the bullet stays in the target:
- Momentum is relevant to moving/tilting the target.
- Energy is relevant to the damage/deformation of target/bullet.

 

[anorlunda]

@Skeet_man do you know how to calculate the kinetic energy and the momentum of a bullet? I

t seems to me that if you were looking at the equations, that you could answer your own question.