In the middle of science class, you have a great idea. being on the fourth floor, you get a friend to watch out the window of the third, second and first floors just beneath you. you have al you friends on a conference call on your cell phone and tell them to let you know when they see a book you drop out you window pass by their window. which statement is true of the amount of time it takes to pass by each window?

a) the time interval between floors is the same.

b) the time interval between floors becomes less each time.

c) the time interval between floors become more each time.

d) the time interval between floors becomes infinitely long.

The ultracentrifuge is an important tool for separating and analyzing proteins. because of the enormous centripetal accelerations, the centrifuge must be carefully balanced, with each sample matched by a sample of identical mass on the opposite side. any difference in the masses of opposing samples creates a net force on the shaft of the rotor, potentially leading to a catastrophic failure of the apparatus. suppose a scientist makes a slight error in sample preparation and one sample has a mass 10 mg larger than the opposing sample. if the samples are 12 cm from the axis of the rotor and the ultracentrifuge spins at 70,000 rpm, what is the magnitude of the net force on the rotor due to the unbalanced samples? ( be thorough on your answer)