You drive in a straight line at 24 m/s for 8 miles, then at 30 m/s for another 8 miles. (a) how does your average speed sav compare with 27.0 m/s (the midpoint of 24 m/s and 30 m/s)?
1) sav < 27.0 m/s
2) sav = 27.0 m/s
3) sav > 27.0 m/s.
explain conceptually.
(b) verify your response to part (a) by calculating the average speed of this trip exactly

Ammonia enters the expansion valve of a refrigeration system at a pressure of 10 bar and a temperature of 18oc and exits at 6.0 bar. the refrigerant undergoes a throttling process. determine the temperature, in oc, and the quality of the refrigerant at the exit of the expansion valve.

Arunner is jogging at a steady 3.6 km/hr. when the runner is 2.9 km from the finish line, a bird begins flying from the runner to the finish line at 14.4 km/hr (4 times as fast as the runner). when the bird reaches the finish line, it turns around and flies back to the runner. even though the bird is a dodo, we will assume that it occupies only one point in space, i.e., a zero-length bird. how far does the bird travel? (b) after this first encounter, the bird then turns around and flies from the runner back to the finish line, turns around again and flies back to the runner. the bird repeats the back and forth trips until the runner reaches the finish line. how far does the bird travel from the beginning? (i.e. include the distance traveled to the first encounter)

How many atoms of nitrogen are in the chemical formula ni(w on