The limit to the eye's visual acuity is related to diffraction by the pupil. D=2.75 mm
dh=1.2 m
a. What is the angle between two just-resolvable points of light for a 2.75 mm diameter pupil in radians, assuming an average wavelength of 550 nm?
b. Take your result to be the practical limit for the eye. What is the greatest possible distance in km a car can be from you if you can resolve its two headlights, given they are 1.2 m apart?
c. What is the distance between two just-resolvable points held at an arm's length (0.800 m) from your eye in mm?

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)