Two Japanese islands are connected by a long rail tunnel that extends horizontally underwater. Imagine a communication system in which a small rail car with a mass of 100.0 kg is launched by a type of cannon in order to transport messages between the two islands. Assume a rail car from one end of the tunnel has a speed of 4.50  102 m/s, which is just large enough for a constant frictional force of 188 N to cause the car to stop at the other end of the tunnel. How long does it take for the car to travel the length of the tunnel? What is the length of the tunnel?

The heater element of a 120 v toaster is a 5.4 m length of nichrome wire, whose diameter is 0.48 mm. the resistivity of nichrome at the operating temperature of the toaster is 1.3 × 10-6 ω·m. the toaster is operated at a voltage of 120 v. (a) what is the power drawn by the toaster? (b) if the cost of electricity is 12 ¢ per kilowatt-hour, and it takes 2 minutes to toast bread, how much does it cost for toasted bread? (c) when the heater element is at room temperature, is the resistivity in the nichrome wire greater than, less than, or equal to it’s resistivity when at operating temperature? explain.