If a bird flaps its wings up and down 50 times in 20s what is the frequency of its flapping

Arotating space station is said to create “artificial gravity”—a loosely-defined term used for an acceleration that would be crudely similar to gravity. the outer wall of the rotating space station would become a floor for the astronauts, and centripetal acceleration supplied by the floor would allow astronauts to exercise and maintain muscle and bone strength more naturally than in non-rotating space environments. if the space station is 200 m in diameter, what angular velocity would produce an “artificial gravity” of 9.80 m/s^{2} 2 at the rim?

Could someone . i have tried to solve myself but my calculation is off

Which of the following is not a transverse wave? a) soundb) lightc) radiod) all of thesee) none of these