What shape can be drawn though a solenoid to determine the magnitude of its magnetic field? A. triangle B. rectangle C. circle D. trapezoid

The answer you want is

Rectangular shape

Explanation: The shape that can be drawn is a rectangular shape, because when we find the magnitude of the magnetic field, we apply Ampere's circuital law to a rectangular loop.

According to Ampere's circuital law, the magnetic field of a solenoid is directly proportional to the product of the current which is flowing around the solenoid and number of turns per unit line of the solenoid.

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