Help me with this problem: Find the magnitude and direction of (a) 9B vector– 3Ā vector and (b) –5Ā vector + 8B vector, where Ā = (23.0, 59.0), B = (90.0, – 150.0).

(With the steps please)

When a book falls from a shelf to the ground without anyone pushing on it, no work is done on the book. true or false

If the ama of the inclined plane below is 2, calculate the ima and efficiency. ima = efficiency =

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.