An evacuated 150-l tank is connected to a line flowing air at room temperature, 25o c, and 8 mpa pressure. the valve is now opened, allowing air to flow into the tank until the pressure reaches 6 mpa, at which time the valve is closed. the filling process occurs rapidly and is essentially adiabatic. the tank is then allowed to sit for a long time with the valve closed, and eventually returns to room temperature. what is the final pressure inside the tank, in mpa? what is the mass of the air that entered the tank, in kg?

As part of your daily workout, you lie on your back and push with your feet against a platform attached to two stiff springs arranged side by side so that they are parallel to each other. when you push the platform, you compress the springs. you do an amount of work of 79.0 j when you compress the springs a distance of 0.230 m from their uncompressed length. (a) what magnitude of force must you apply to hold the platform in this position? (b)how much additional work must you do to move the platform a distance 0.230 m farther? (c) what maximum force must you apply to move the platform a distance 0.230 m farther?