The relative velocity of a swimmer with respect to earth is 15km/hr when swimming with the stream and 5km/hr when swimming against stream. Find (i) velocity of water current, (ii)velocity of swimmer in still water.

initial speed when it is dropped is 150 ft/s

now at the same moment the acceleration due to gravity is perpendicular to its velocity

so as we know that

now we have centripetal acceleration a = 32 ft/s^2 as its perpendicular to velocity

while tangential acceleration at the same moment will be zero

so

now radius of curvature is given as

so the radius of curvature just after it is dropped is 703.125 ft