Abb gun is discharged at a cardboard box of mass m2 = 0.65 kg on a frictionless surface. the bb has a mass of m1 = 0.012 kg and flys at a velocity of v1 = 99 m/s. it is observed that the box is moving at a velocity of v2 = 0.39 m/s after the bb passes through it.1. write an expression for the magnitude of the bb's velocity as it exits the box vf.2. what is the bb's final velocity vf, in meters per second?
3. if the bb doesn't exit the box, what will the velocity of the box v'2, be in meters per second?

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Which statement correctly describes the current in a circuit that is made up of any two resistors connected in parallel with a battery? a. the current in the battery and in each resistor is the same b. the current the battery equals to the sum of the currents in the resistors c.the current in the battery is less than the current in either resistor d. the current in the battery equals to the product of the currents in the resistors

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)