As we can see in the illustration, Jeff stepped on the end of the board or lever and caused a huge, 600 pound rock to be lifted in the air. The BEST explanation of what happened is

Jeff did work

The rock did work

No work was done because the lever was used

No work was done because the rock was moved vertically

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.

How does the formation of intrusive and extrusive igneous rocks differ?

Two blocks of aluminum (specific heat c=0.22 cal/g celsius) with masses of 1000 g and 100 g are at a temperature of 70 c. which block has more thermal (internal) energy? explain why?