During the broom race, Amanda uses the Shooting Star to try and win, but Akko boards it and it flies around the world, including emerging from the water with enough force to create a colossal pillar of water that reaches far above cloud level. We also see that the broom race around Luna Nova continues that same day, with no waiting around for Akko to return. First let's get a high end. The Earth is 40,075km in circumference, so what's the timeframe?
T = 40,075km/29s
= 1381896.55/340.29
= Mach 4060.93788
We can also find the kinetic energy for Akko's durability (Akko ends this covered in scratches, so it would be more than reasonable, as well as the colossal explosion of water). Akko weighs 46kg.
= (0.5) X 46 X 1381896.55^2
= 4.39216757e13 joules
That's impressive enough by itself, but wait! At one point, Akko flies through the ocean and emerges a few seconds later in a place where the sky is a different colour.
Thing is, this is travelling through water, which is far more viscous that air. The viscosity of water is 8.90e-4 Pa*S (or kg per m^2), while the viscosity of air is while the viscosity of air is 1.81e-5 kg/m^2.
8.90e-4/1.81e-5 = 49.1712707
Ergo, water is 49.1712707 times more viscous than air. Given this is also and it would take 49.1712707 times more energy to move through it.
E = 4.39216757e13 X 49.1712707
= 2.15968461e15 joules
= 516.177010038240951 kilotons
Let's also go with a low end, of the time it took Akko to fly from England to Finland. We can tell it's Finland because it has the same Yeti. Luna Nova is located in England on the St. Michael Alignment, which is based off the Leylines from British folklore.
1 pixel = 804.67200km/139 = 5.78900719km
5.78900719km X 321 = 1858.27131km
How long did it take?
T = 1858.27131km/8s
= 232283.914/340.29
= Mach 682.60576
KE = (0.5)mv^2
= (0.5) X 46 X 232283.914^2
= 1.24098378e12 joules
E = 1.24098378e12 X 49.1712707^2
= 6.10207494e13 joules
= 14.58430913001912 kilotons
Now let's also find the one for the underwater part. We see her enter at mid-day, then bursts out at night, so that's around 6 time zones. The circumference of the Earth is 40,075km.
L = 40,075km/24
= 1669.79167km X 6
= 10018.75km
Next for the timeframe (we also see the Sun is at it's zenit).
T = 10018.75km/6s
= 1669791.67/340.29
That's the highest result yet! But what about the kinetic energy?
KE = (0.5)mv^2
= (0.5) X 46 X 1669791.67^2
= 6.41286971e13 joules
E = 6.41286971e13 X 49.1712707
= 3.15328952e15 joules
= 753.6542829827916421 kilotons
Final Results
Shooting Star speed (low end) = Mach 682.606
Shooting Star speed (mid end) = Mach 4060.938
Shooting Star speed (high end) = Mach 4906.967
Akko's kinetic energy on the Shooting Star (low end) = 14.584 kilotons
Akko's kinetic energy on the Shooting Star (mid end) = 516.177 kilotons
Akko's kinetic energy on the Shooting Star (high end) = 753.654 kilotons
