This assumes that the wave has velocity c (is light).
If it's not moving at all at the beginning of the 10 seconds, then it falls 490 meters straight down in 10 seconds.
(Note: This is true of all objects on Earth . . . rubber balls, feathers, grains of sand, school buses, battle ships . . . everything. As long as air doesn't hold them back. Anything falling from rest falls 490 meters in the first 10 seconds.)
Answer:5
Explanation:
Given
speed of object 
radius of circle 
Force towards the center 
Work done is given by the dot product of Force and displacement
and we know know displacement of the object is along the circle which is perpendicular to the force acting therefore Work done will be zero

