In 1980, over San Francisco Bay, a large yo-yo was released from a crane. Suppose the yo-yo was 108 kg, and it consisted of two uniform disks of radius 40.0 cm connected by an axle of radius 4.00 cm. What was the magnitude of the acceleration of the yo-yo during (a) its fall and (b) its rise

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)

In a hydrogen molecule there are a total of four charges, 2 protons in the two nuclei, and 2 electrons. how many unique charge-pairs are there (without double counting)?

The first law of thermodynamics states that heat added to a system is neither created nor destroyed but is as it changes into other forms of energy.