Highway safety engineers build soft barriers so that cars hitting them will slow down at a safe rate. a person wearing a safety belt can withstand an acceleration of 300 m/s 2 . how thick should barriers be to safely stop a car that hits the barriers at 92.8 km/h? answer in units of m.

Two kilograms of air within a piston–cylinder assembly executes a carnot power cycle with maximum and minimum temperatures of 800 k and 300 k, respectively. the heat transfer to the air during the isothermal expansion is 60 kj. at the end of the isothermal expansion the volume is 0.4 m3. assume the ideal gas model for the air. determine the thermal efficiency, the volume at the beginning of the isothermal expansion, in m3, and the work during the adiabatic expansion, in kj.