two loudspeakers are placed side by side and driven by the same source at 500 hz. a listener is positioned in front of the two speakers and on the line separating them, thus creating a constructive interference at the listener's ear. if one of the speakers is gradually pushed toward the listener, how far must it be moved to repeat the condition of constructive interference at the listener's ear? (the speed of sound = 340 m/s.)

The distance d that a car can travel in a certain amount of time t can be found by multiplying the rate of speed r by the travel time. if a car has already travel 4 miles, the formula for the total distance travel is d= rt + 4. which of the following gives the value of r, in terms of d and t?

If you perfer to learn by reading to yourself instead of participating in a group discussing, you are most likely an

In the image, layer a is the topmost layer. layer c contains fossils from the precambrian era. layer b contains dinosaur fossils, and layer a contains fossils of mammals. which two statements are supported by this evidence? 1. mammals lived before the precambrian era. 2. dinosaurs and mammals existed in the precambrian era. 3. dinosaurs evolved after precambrian organisms. 4. precambrian organisms evolved after dinosaurs. 5. precambrian organisms were the first life-forms to become fossilized, according to this sample.