An air-filled pipe is found to have successive harmonics at 800 {\rm Hz} , 1120 {\rm Hz} , and 1440 {\rm Hz} . It is unknown whether harmonics below 800 {\rm Hz} and above 1440 {\rm Hz} exist in the pipe. What is the length of the pipe?

Plss anybody know how to do this? ? i need the answers from a through d

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)

What is the weight of a 8-kg substance in n, kn, kg·m/s2, kgf, lbm·ft/s2, and lbf?