- Fuel is a source of mechanical energy for cars to move
- The car runs out of fuel
- Therefore, the car does not have a source of mechanical energy to move

- A car is moving on a level road
- If one surface is moving on another surface then those surfaces are touching
- Therefore, the moving car and the road are touching on their surfaces

- If an object is not moving it does not have any motion to counter
- Friction acts to counter the motion of two objects when their surfaces are touching
- Therefore, friction acts to counter the motion of only moving objects when the surfaces of two objects are touching

- The moving car and the road are touching on their surfaces
- Friction acts to counter the motion of only moving objects when the surfaces of two objects are touching
- So, friction will counter the motion of the moving car

- Friction will counter the motion of the moving car
- Countering the motion of a moving object means decreasing the mechanical energy of the moving object
- So, friction will decrease the mechanical energy of the moving car

- The car does not have a source of mechanical energy to move
- Friction will decrease the mechanical energy of the moving car
- Hence, the car does not have a source of mechanical energy and friction will decrease the mechanical energy of the moving car

- The car does not have a source of mechanical energy and friction will decrease the mechanical energy of the moving car
- If something is decreased and there is no source of that something to provide more of that something, then that something will decrease to 0
- So, the mechanical energy of the moving car will be decreased by friction to 0

- The mechanical energy of the moving car will be decreased by friction to 0
- If an object has 0 mechanical energy, then the object will stop moving
- So, the car will stop when the mechanical energy in it is decreased by friction to 0

So, the car will stop when the mechanical energy in it is decreased by friction to 0
A car runs out of fuel while traveling on a level road and eventually comes to a stop. Which of the following best explains why the car stops?
- Fuel is a source of mechanical energy for cars to move 
- If an object is not moving it does not have any motion to counter 
- A car is moving on a level road 
- If an object has 0 mechanical energy, then the object will stop moving 
- The car runs out of fuel 
- If one surface is moving on another surface then those surfaces are touching 
- Friction acts to counter the motion of two objects when their surfaces are touching 
- If something is decreased and there is no source of that something to provide more of that something, then that something will decrease to 0 
- Countering the motion of a moving object means decreasing the mechanical energy of the moving object