When you whirl a small rubber stopper on a cord in a vertical circle, you find a critical speed at the top for which the tension in the cord is zero. At this speed. the force of gravity on the object 1S itselfisufficient to supply the necessary centripetal force. How slowly can you swing a 15-g stopper like this so that It will just follow a circle with a radius of m?

Which of the following represents an upright image? a. -do b. +m c. -m d. +do

Asystem containing an ideal gas at a constant pressure of 1.22×10^5 pa gains 2140 j of heat. during the process, the internal energy of the system increases by 2320 j. what is the change in volume of the gas?

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)