A car travels east with a certain constant velocity. The direction of the friction force on the car is

Options

A. due east
B. due west
C. up
D. zero

Explanation

To determine the direction of the friction force acting on a car that travels east with a constant velocity, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Constant Velocity**:
- The car is moving east with a constant velocity. This means that the speed and direction of the car are not changing.

**Hint**: Remember that constant velocity implies no net acceleration.

2. **Identifying Forces Acting on the Car**:
- When a car is in motion, there are forces acting on it. The main forces to consider are the driving force (from the engine) and the frictional force opposing the motion.

**Hint**: Think about what forces are necessary for the car to maintain its speed.

3. **Applying Newton's First Law**:
- According to Newton's First Law, if the velocity of an object is constant, the net force acting on it must be zero. This means that all forces acting on the car must balance each other out.

**Hint**: Net force being zero means that the forces are in equilibrium.

4. **Direction of the Driving Force**:
- Since the car is moving east, the driving force exerted by the engine is also directed east.

**Hint**: Consider which way the car's engine is pushing the car.

5. **Direction of Frictional Force**:
- The frictional force always acts in the opposite direction to the motion of the object. Therefore, if the car is moving east, the frictional force will act to the west.

**Hint**: Remember that friction opposes motion.

6. **Conclusion**:
- Since the car is moving east and the frictional force opposes this motion, the direction of the friction force acting on the car is towards the west.

**Final Answer**: The direction of the friction force on the car is **west**.