In an effort to reduce greenhouse gas (ghg) emissions and improve fuel use, the environmental protection agency (epa) and the national highway traffic safety administration (nhtsa) are coordinating standards for the production of clean vehicles through. which is not true as the regulations become stricter? a) cars and trucks have larger engines. b) vehicles have increased fuel economy. c) more efficient engines decrease emissions. d) better emission filters diminish emissions.

Wo audio speakers are placed on a vertical rail. speaker a is placed at head-level while speaker b is place at some variable height, \delta yδy, above speaker a. both speakers receive simultaneous input from a sine-wave generator so the speakers each produce a pure sinusoidal sound wave with a wavelength of 0.531 meters. calculate the lowest height that speaker b can be placed above speaker a to produce a minimum of sound heard by person standing \delta x = 7.86δx=7.86 meters directly in front of speaker a.

Refrigerant-134a flows through a carnot heat pump cycle at 0.5 kg/s. it is known that the maximum absolute temperature in the cycle is 1.1 times the minimum absolute temperature, and the net power input to the cycle is 2.5 kw. if the refrigerant changes from a saturated vapor to a saturated liquid during the heat rejection process, determine the maximum magnitude of the enthalpy of vaporization for this process in kj/kg (with 3 significant figures).

Where should a carbon monoxide detector be mounted?