Motion of the arm of a soldier marching along the road

The correct answer is option 'A': Oscillatory

Explanation:

When a soldier is marching along the road, the motion of their arm can be categorized as oscillatory. Let's understand why:

1. Oscillatory motion:
Oscillatory motion refers to the repetitive back and forth or to and fro motion around a central position. In this type of motion, the object or body moves repeatedly between two extreme positions. Examples of oscillatory motion include the swinging of a pendulum, vibration of a guitar string, or the motion of a swing.

2. Motion of the soldier's arm:
When a soldier marches along the road, their arm moves in a repetitive manner. The arm swings back and forth in synchronization with their walking or marching steps. The arm moves forward and then backward, and this motion repeats continuously as the soldier continues their march.

3. Characteristics of oscillatory motion:
Oscillatory motion has certain characteristic properties, some of which are observed in the motion of the soldier's arm:

- Periodic: Oscillatory motion is periodic, meaning it repeats itself after a fixed interval of time. Similarly, the soldier's arm swings back and forth in a regular and repetitive manner as they continue marching.
- To and fro motion: In oscillatory motion, the object or body moves in a to and fro pattern around a central position. The soldier's arm moves forward and backward in a repetitive manner, maintaining a central position around the shoulder joint.
- Fixed amplitude: The amplitude of oscillatory motion remains constant. In the case of the soldier's arm, the distance it swings forward and backward remains the same for each repetition.

Therefore, based on the characteristics of oscillatory motion and the repetitive back and forth motion of the soldier's arm while marching, we can conclude that the motion of the soldier's arm is oscillatory.

Answer is a