The humphreys series is a group of lines in the spectrum of atomic hydrogen. it begins at 12 368 nm and has been traced to 3281.4 nm. what are the transitions involved? what are the wavelengths of the intermediate transitions?

An object moves from the position +34m to the position -15m in 15 seconds. what is it's total displacement? what is it's average velocity?

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)

You need to fill a basketball with air to play with it. you know that your pump expels air at a velocity of 6 cm/s. you know that the volume flow rate of air being pumped into the basketball is 103 cm^3/s. what is the diameter of your needle?