A sound source is producing the wave fronts shown above as it moves. At what point above would an observer hear a higher frequency than the original source?

Thomas his older brothers, who own a junk yard, on the weekends to earn extra money. he likes to them push broken-down cars to the back of the junk yard because it makes him feel strong. last saturday, they pushed three cars with different weights, and he noticed he used different amounts of force for each one. the cars were the following weights: white car: 2,700 kg red car: 1,500 kg blue car: 2,100 kg think about how much force is needed to move each car. which correctly lists the cars in order from the most to least amount of force needed to move them? a) white, blue, red b) blue, red, white c) red, white, blue d) white, red, blue

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.

Gordon is going for a run through the park, but it is cold outside. the low outside temperature could affect his personal safety.