So since those Kinetic Energy feats weren't acceptable, it's time I move on to the other calcs I made.
AP Feats
Hookfang Destroys a Tree
(Evaluated as "fine")
In Dragons: Defenders of Berk Ep. 15, Hookfang breathes some fire at a pine tree, reducing it to ashes in seconds. I'll be using the formula for heat increase, so I'll find mass first.
A quick Google search tells me that pine trees can grow to 150ft tall, or 46m.
Height=554px=46m
Width=28px
Height Destroyed=432px
46/554=0.083m/px
28*0.083=2.3m, 1.15m radius
432*0.083=36m
π*1.15^2*36=149.57m^3, or 5,282ft^3
Average density of pine wood is 30lb/ft^3
5282*30=158460lbs, or 71,876.3kg
To find change in temperature, I started with a room temperature of 20 C. According to https://sciencing.com/hot-bonfire-8770.html, the charcoals of a bonfire exceed temperatures of 1,100 C. Seeing as there were no coals left over, I'm going to use this value for my calc.
1100-20=1080 C
Plugging my values into this calculator https://www.omnicalculator.com/physics/specific-heat (and choosing wood as my substance), I get a result of 1.32e11 Joules, City Block level. This would probably scale to a majority of dragons.
Stormfly Melts a Boulder
(Evaluated as "fine")
In Dragons: Defenders of Berk Ep. 15, Stormfly up & melts a boulder/rock formation in the ocean. I'll treat the rock as a cylinder & use the formula for increasing temperature. First, I'll find mass.
Stormfly=9.14m=320px
Rock Height=594px
Rock Diameter=258px
9.14/320=0.03m/px
594*0.03=17.82m
258*0.03=7.74m, 3.87m radius
π*3.87^2*17.82=838.45m^3
According to http://www.greenspec.co.uk/building-design/thermal-mass/, density of stone is 2,300kg/m^3.
838.45*2300=1928435kg
Also according to the link above, the specific heat capacity of stone is 1000 J/kg K.
Finally, we find change in temperature. Starting with a room temperature of 20 C, magma can reach heats up to 1600 C.
1600-20=1580 C
Plugging all this into this calculator https://www.omnicalculator.com/physics/specific-heat, I get 3.05e12 Joules, Multi-City Block level+. Deadly Nadders have notoriously hot fire (said to be as hot as the Sun even), so I doubt this'd scale to most dragons.
Striking Strength/Durability Feats
Screaming Death Smashes Rocks
(Evaluated as "fine")
In episode 4 of Defenders of Berk, the Screaming Death smashes through some rock formations. You can just barely see Toothless behind the very blurry rock.
Toothless=346px=8m
Rock Height=632px
Rock Diameter=315px
8/346=0.02m/px
632*0.02=12.6m
315*0.02=6.3m, 3.15m radius
π*3.15^2*12.6=392.77m^3, 392770000
I'm almost positive that this is Violent Fragmetation, so.
3.9e8*69=2.7e10 Joules, Large Building level+. This is probably a lowballed value since the whole rock wasn't on screen.
Thunderdrum Smashes Rocks
(Evaluated as "fine")
In Episode 19 of Riders of Berk, a Thunderdrum smashes some rocks. Dragon sizes can be kind of inconsistent, but Gronckle should be pretty safe. Meatlug here is slightly shorter than Fishlegs, who's about 5'9", so I think it's safe to assume she's 1.5m tall.
Meatlug=52px=1.5m
Rock Height=203px
Rock Diameter=37px
1.5/52=0.0288m/px
203*0.0288=5.8m
37*0.0288=1m, 0.5m radius
π*0.5^2*5.8=4.56m^3, 4560000 cm^3
Once again, Violent Fragmentation.
4.5e6*69=3.1e8 Joules, Small Building level. This should be good to scale most dragons to.
Skullcrusher Knocks Over a Rock
(Unevaluated)
In S1 Ep8 of Race to the Edge, Skullcrusher knocks over a big rock.
Mass
Judging by this image [1], Skullcrusher's about 3.35m tall. Pixel scaling is weird cause motion blur, but should be fine.
Skullcrusher=54px=3.35m
Rock Diameter=682px
3.35/54=0.06m/px
682*0.06=41m diameter
Bottom Rock Diameter=271px=41m
Bottom Rock Height=250px
41/271=0.15m/px
250*0.15=37.5m
π*20.5^2*37.5=49509.54m^3
Middle Rock Diameter=235px
Middle Rock Height=198px
235*0.15=35.25m
198*0.15=30m
π*17.6^2*30=29194.19m^3
Top Rock Diameter=269px
Top Rock Height=99px
269*0.15=40.35m
99*0.15=15m
π*20^2*15=18849.56m^3
49509.54+29194.19+18849.56=97553.29m^3
97553.29*1602=1.56e8kg, Class M
Kinetic Energy
Here, I'm gonna take the height of the rock, & use it as radius to find circumference. Then I'll use 1/4 of that circumference as distance traveled.
37.5+30+15=82.5m
π*165=518m
518*0.25=129.5m
From when Skullcrusher hit it, to the rock hitting the ground, about 2 seconds pass.
129.5/2=64.75m/s
1.56e8*0.5*64.75^2=3.2e11 Joules, City Block level+. Looks good for general dragons.