The chart shows data for four heat engines.

A 3 column table with 4 rows. The first column is labeled heat engine with entries W, X, Y, Z. The second column is labeled T Subscript h Baseline in Kelvin with entries 620, 840, 900, 500. The last column is labeled T Subscript c Baseline in Kelvin with entries 120, 100, 300, 25.

Which lists the engines from most efficient to least efficient?

Y, X, W, Z
Z, W, X, Y
Z, X, W, Y
Y, W, X, Z

These models show the electron structures of two different nonmetal elements. which element is likely more reactive, and why? element 1 is more reactive because it has fewer electron shells and is toward the top of its group on the periodic table. element 1 is more reactive because it has more electrons in its valence shell and is farther to the right on the periodic table. element 2 is more reactive because it does not have a valence shell close to the nucleus, so it will attract electrons. element 2 is more reactive because it does not have a full valence shell, so it will attract electrons.

Assume similar data for the motion of the blood in your aorta. estimate how many beats of the heart it will take the blood to get from your heart to your brain. (assume that the distance from your heart to your brain is 30 cm)

Africtionless piston-cylinder contains 50 l of saturated liquid r-134a. the piston has a mass and an area resulting in an applied pressure of 500 kpa on the refrigerant. the refrigerant is now heated until its temperature rises to 70∘c. calculate the work (in kj) done during this process.