The photo shows a pair of figure skaters performing a spin maneuver. The axis of rotation goes through the left foot of the skater on the left. What
change could the pair make that would result in no change to their angular
velocity?
O A. The skater on the right extends her left leg to the right.
B. The skater on the left allows the distance between the pair to
increase.
O C. The skater on the left pulls the skater on the right closer to him.
D. The skater on the left points his right arm down instead of up.

Which of the following represents an upright image? a. -do b. +m c. -m d. +do

Acompound machine is also called a machine. a. force b. simple c. complex d. directional

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)