Question

Consider an automobile traveling at a constant speed along a road. Determine the direction of the heat and work interactions, taking the following as the system:

(a) the car radiator,
(b) the car engine,
(c) the car wheels,
(d) the road, and
(e) the air surrounding the car.

Answer 1

The direction of heat and work interactions in an automobile involves heat transfer from the radiator, work by the engine, work on the wheels, and work on the road and surrounding air.

Step-by-step explanation:

The direction of heat and work interactions in a traveling automobile can be explained by considering several components of the car:

• (a) Car radiator: Heat transfers out of the system from the radiator into the surrounding air, cooling the engine.
• (b) Car engine: Work is done by the system as it turns chemical energy into kinetic energy and heat.
• (c) Car wheels: Work is done on the system by transferring energy from the engine to the wheels, propelling the car forward.
• (d) Road: The road does work on the car by exerting a frictional force, which is converted into heat.
• (e) Air surrounding the car: Work is done by the system against the air to overcome air resistance, and heat from the engine and frictional forces is transferred to the air.

In the context of thermodynamics and energy conservation, these interactions define how energy is transferred within the car and between the car and its environment.