Amoving sound source a has a velocity (85 km/hr) \widehat{i\ } and a moving reflecting surface b has a velocity (75 km/hr) (-\ \widehat{i\ }). the source a emits a sound with a frequency of 39 khz. a) assuming b is approaching a find the frequency as heard by b b) assuming b is moving away from a, find the frequency as heard by b c) what is the frequency of the reflected beam to the source (pick (b) as the set-up to answer this question). speed of sound in air 340 m/s

1) what is the power in horsepower of a 100 watt light bulb? what is the power in kilowatts of a 200 horsepower engine? 2) if a cars engine is providing 3000 n of force to keep the car moving at 5 m/s, what is the engine’s effective power? 3) how many gallons of water will be pumped from a well 30 feet deep by a 1/2 hp engine in 1 minute? (1 gallon weighs 8.34 pounds)

Which radioisotope is used in dating geological formations?

Your physics assignment is to figure out a way to use electricity to launch a small 6.0-cm-long plastic drink stirrer. you decide that you'll charge the little plastic rod by rubbing it with fur, then hold it near a long, charged wire, as shown in figure p23.56 . when you let go, the electric force of the wire on the plastic rod will shoot it away. suppose you can uniformly charge the plastic stirrer to 10 nc and that the linear charge density of the long wire is 1.0 x10-7 c/m. what is the net electric force on the plastic stirrer if the end closest to the wire is 2.0 cm away?