A circular bowl of diameter 400 mm contains water at rest. If its side is tapped gently, a completely circular pulse can be produced on the surface of the water which travels inwards with a speed of 250 mm s-1. The radius of the pulse and its direction of travel, 1 s after the pulse is produced, are
A zero, stationary
B 50 mm, outwards
C 50 mm, inwards
D 150 mm, outwards
Update: Edit to look nicer
I guess it's B right?
Because the diamenter of the bowl is 400mm, the radius is 200mm. The speed of the water wave is always 250mm/s. In one second the wave will travel a distance 250mm. But then this is more than the radius of the bowl. So that means that the wave go inward for 200mm then go 50mm outward.