Friends tell you that on a recent trip their average velocity was +20 m/s. Is it possible that at any time during their trip their velocity was -20 m/s? Explain, and give an example to justify your answer. PLEASE HELP

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)

Suppose the house in question 3 is located in cleveland where the annual average solar flux is 160 w/m2 . if 10 m2 of solar panels operating at 20 percent efficiency were installed on this house to collect and store solar energy in the form of hot water:

Protein provides 4 calories per gram. mary is on a diet that requires her to eat at least 40 grams of protein each day.she's eaten 152 calories of protein today.howmuch more protein does mary need to eat to meet her goal