Bob roller skates with a constant speed of 6 miles per hour. How long will he take to travel a distance of 128 miles ?

Describe the path of a ray that approaches a mirror parallel to the principal axis.

Which branches of natural science include the study of an organism that lived 10 million years ago

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.