When two sources of waves with the same frequency are active, what must the path length difference be at some point in space for the waves to interfere destructively?.

the second one and the forth one are in the purple because they are opinions and the rest are in the yellow

explanation:

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

explanation:

wheres the pic