How long have humans been migrating?
А
2,000 years
about 200,000 years
about 60,000 years
D
1,000 years

Phase changes are chemical changes. true or false

Can you match these to the correct definition

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.