A2000 hz siren and a civil defense official are both at rest with respect to the ground. what frequency does the official hear if the wind is blowing at 12 m/s (a) from source to official and (b) from official to source?

Which is not a source of noise pollution? a)airplanes b)acid rain c)machines d)cars

A30 kg weight lies on top of a massless piston of area a = 0.01 m2 the exterior air is at a (constant) p =1 atm and t = 27 c. the interior gas is 0.4 moles of (ideal) n2 and it has initial temperature 27.00 degrees c. 1. what is the initial pressure in the interior? a. 29.4 kpa b. 130.7 kpa c. 101.3 kpa the next three questions concern what happens when an amount of heat q is slowly added to the interior, raising the piston by 1 mm and raising the interior temperature to 27.40 c

Road users moving into your lane, brake lights, and abrupt changes in road surface are a. rare at night b. indicators of potential hazards c. not worth worrying about before you reach them d. no problem for experienced drivers