1. The problem statement, all variables and given/known data Calculate the torque, angular momentum and kinetic energy of the water wheels in the table. [I'll give one example] High breast water wheel: Angular velocity/rpm 8 Head/m 4.65 Flow rate*/m3 s−1 1.0 Power/kW 39.4 Diameter/m 7.0 Width or height/m 2.5 Mass/kg 14 143 Power-to-weight ratio/W kg−1 2.8 2. Relevant equations Torque = Moment of inertia * Angular acceleration Moment of inertia of thin solid disc = (mr^2)/2 (about z axis) Angular momentum = Moment of inertia * Angular velocity Rotational kinetic energy = (Iw^2)/2 3. The attempt at a solution 8rpm -> (8/60)*2*pi rad/s = (4pi)/15 rad/s Torque = (14143*3.5^2*(angular velocity))/2 = 72572Nm Angular velocity has here been used instead of angular acceleration due to explanation found here: https://www.physicsforums.com/showthread.php?t=346163 However, this means that the angular momentum calculation gives the same answer (minus a direction, which will take the direction of the angular velocity vector). Have I done this correctly? Rotational KE = (14143*3.5^2*((4pi)/15)^2)/2 = 60797J Do these seem at all right?