12 The diagram shows two blocks of a material whose critical angle is 40°. In block A, the ray strikes the inner surface with an angle of incidence of 30°. In block B, the ray's
angle of incidence is 50°.
a Copy and complete each diagram to show what happens when the ray strikes the surface.
Use the diagrams to explain what is meant by total internal reflection.

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