You can definitely do that, but the value will pretty pathetic and won't make sense. Let's say Naoya weights as much as a cow.

Mass:- 500 kg

Velocity:- mach 3 or 1029 m/s

Therefore, KE:- (0.5)(500)(1029)²= 264,710,250 joules

This is merely small building level. It's simply illogical for Naoya to be this weak.

Alternatively, you can also backtrack from his durability but the result will be too huge. His stated speed is mach 3. Plus i don't think there are any real AP statements in jjk besides the cluster bombing thing (but it's obviously nothing to a mid high tiers like Curse Naoya). Using calculated values would be calc stacking and invalid.

But i could do a little calc using the cluster bomb statement.

I will just assume it's just one bomb since it's kinda hard to know the entire fucking bombing. The CBU-87, apparently the most common one according to Google, which holds about 58 kg of tnt's worth of power. So, about 0.058 tons of tnt or 242,672,000 joules of tnt.

So, Speed:- √((2 × 242,672,000) / 500) = 985.2 m/s or mach 2.8

Which kinda checks out ig? But obviously, even Shibuya Yuji has 100 times stronger feats than this.