How can you show positive body languages with your mouth

An insulated 40 ft^3 rigid tank contains air at 50 psia and 120°f. a valve connected to the tank is now opened, and air is allowed to escape until the pressure inside drops to 25 psia. the air temperature during this process is kept constant by an electric resistance heater placed in the tank. determine the electrical work done during this process.

Which word expression describes how much to calculate pressure

Using the free-body diagram, calculate the net force acting on the sled. is the sled in a state of dynamic equilibrium?