It is due tomorrow and i don’t understand it..

Acar drives toward the right over the top of a hill, as shown below. which arrow represents the centripetal acceleration? w x y z

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.

You can decrease the resistance of a length of wire by