In an experiment to determine the acceleration due to gravity, one student drops a tennis ball out of the school’s third floor window. Another student starts a timer when the first student lets go and stops the timer when the ball hits the ground. They conduct the experiment once and record the data. Is this a valid experiment, why or why not?

there is no correct list among the choices you've provided.

the list might look something like this:

-- baby human

-- piccolo

-- flute

-- soprano singer

-- trumpet

-- tenor singer

-- trombone

-- baritone singer

-- baritone horn

-- bass singer

-- tuba

since i had to make up the list myself, i made it easy on myself, and i didn't try to shuffle the string instruments and woodwinds into it too.

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

electric field is a function of 1/r^2

yes, the force per unit charge for a point charge is inverse square law.