I got frequency of chocolate 2.5 x10^9
It was the antinodes i think because it was the point were it was max oscillations/displacements which caused the melting
I chose material B and C for the ropes and lift (can't remember which way which but I did explain it so hoping at least 3/6 if am lucky
Moment of the air increased? Because direction and mass is the same but speed increased
Momentum at the end changes because the direction of the air changes??
Was the runway something like 850m (which I think is too long personally)