How was hubble important to our understanding of galaxies?

Which of the following are considered noble gases? a. bromine b. neon c. argon d. chlorine

The coefficient of friction is a number that represents the resistance to sliding between two in contact with one another.

The space between two 15-in.-long concentric cylinders is filled with glycerin (viscosity = 8.5 × 10-3 lb·s/ft2). the inner cylinder has a radius of 1 in. and the gap width between cylinders is 0.1 in. determine (a) the torque and (b) the power required to rotate the inner cylinder at 180 rev/min. the outer cylinder is fixed. assume the velocity distribution in the gap to be linear.