STATEMENT-1 : For an observer looking out through the window of a fast moving train, the nearby objects appear to move in the opposite direction to the train, while the distant objects appear to be stationary. STATEMENT-2 : If the observer and the object are moving at velocities and respectively with reference to a laboratory frame, the velocity of the object with respect to the observer is .
Answer: B. Statement-1 is True, Statement-2 is True; Statement-2 is NOT a correct explanation for Statement-1
Or read the worked solution below. Jump to the steps ↓
Written solution
Step 1: Analyze Statement-2.
The relative velocity of an object with respect to an observer is defined by the vector difference of their velocities in a common reference frame.
This is a standard definition and is always true. Thus, Statement-2 is true.
Step 2: Analyze Statement-1.
For stationary objects on the ground, their velocity in the laboratory frame is , meaning their relative velocity with respect to the train is constant.
The apparent motion perceived by the observer is determined by the angular velocity , which is the rate of change of the line-of-sight angle .
For nearby objects, the distance is small, resulting in a large angular velocity , so they appear to move rapidly backward.
For distant objects, the distance is very large, making , so they appear stationary. Thus, Statement-1 is true.
Step 3: Evaluate the relationship between the statements.
The relative velocity is the same for both near and distant objects and does not depend on distance.
Since the explanation for Statement-1 relies on the distance-dependent angular velocity , Statement-2 is not the correct explanation for Statement-1.
Answer: Statement-1 is true, Statement-2 is true; Statement-2 is not a correct explanation for Statement-1.