A disk has a radius of 30 cm and a mass of 0.3 kg and is turning at 3.0 rev/s. A trickle of sand falls onto the disk at a distance of 20 cm from the center and build a 20cm radius ring of sand on it. How much sand must fall on the disk to decrease the speed to 2.0 rev/s? Idisk = 1 2mR2 ; Iring = mR

Stars x and y are both bluish main sequence stars. star x has a higher absolute brightness than star y. how do the two stars compare? explain

Agas contained within a piston-cylinder assembly undergoes three processes in series: process 12: compression with pv= constant from 1 bar and 1 liter to 4 bar. process 23: constant pressure expansion to 1 liter. process 31: constant volume calculate the pressure and volume at each state, and sketch the processes on a p-vdiagram labeled with pressure and volume values at each numbered stat

How much energy must a refrigerator absorb from 225 g of water so that the temperature of the water will drop from 35°c to 5°c