ω=90(π/30)=3π rad/sec
Vtank=14πD2H=14π(1.32)(2.1)
Vtank=2.7874 m2
Vw1=14πD2d=14π(1.32)(1.4)
Vw1=1.8582 m3
h=ω2r22g=(3π)2(0.652)2(9.81)
h=1.9128 m ← [ B ] answer for part 1
h/2=0.9564 m
Since h/2 > 0.7 m, water are spilled from the tank
Vair=12πr2h=12π(0.652)(1.9128)
Vair=1.2694 m3
Vw2=Vtank−Vair=2.7874−1.2694
Vw2=1.518 m3
Vspilled=Vw1−Vw2=1.8582−1.518
Vspilled=0.3402 m3=340.2 Liters ← [ C ] answer for part 2
So that no water is spilled out
H=1.4+h/2=1.4+0.9564
H=2.3564 m ← [ D ] answer for part 3