Relative motion
Explanation
In physics, motion is not absolute but depends on the observer's frame of reference. The state of rest or motion of an object is always described relative to a specific reference point.
Detailed Analysis:
- Relative Motion (Correct): The passenger is in a moving frame of reference (the bus). While the trees are stationary with respect to the ground, their position changes relative to the passenger as the bus moves forward. Mathematically, the relative velocity of the trees with respect to the passenger is \(\vec{v}_{trees} - \vec{v}_{bus}\). Since \(\vec{v}_{trees}\) is zero and \(\vec{v}_{bus}\) is positive (forward), the result is negative (backward). Thus, the trees appear to move backward.
- Absolute Motion: In classical mechanics, there is no concept of absolute motion or absolute rest. All motion is defined relative to a chosen frame of reference.
- Coriolis Effect: This refers to the deflection of moving objects when viewed in a rotating reference frame, such as the deflection of winds due to the Earth's rotation. It is not relevant to linear motion on a road.
- Inertial Resistance: This refers to the property of matter (inertia) by which it resists changes in its state of motion. While inertia explains why a passenger feels a jerk when the bus accelerates, it does not explain the visual perception of stationary objects moving backward.
Key Takeaway:
Motion is always relative. An object that is stationary in one frame of reference (ground) can appear to be moving in another frame of reference (moving bus).