A man started at his house and went 3 miles to the post office, then he went 4 miles to the pet store, and finally he went 5 miles home again. What
is the average velocity if his trip took 3 hours?*

In what direction does the medium move relative to the direction of the wave? explain.

J. j. thomson’s experiment disproved the theory that an atom

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.