Displacement-time graph

Definition

A displacement-time graph is a visual representation that shows the displacement of an object over time. The graph plots displacement on the vertical axis and time on the horizontal axis, illustrating how far an object has moved from its starting position at various points in time. In the context of simple harmonic motion, this graph is particularly useful as it can demonstrate periodic motion, showcasing how displacement changes sinusoidally over time.

5 Must Know Facts For Your Next Test

1. The slope of a displacement-time graph indicates the velocity of the object; a steep slope means higher velocity, while a flat slope indicates the object is at rest.
2. In a simple harmonic motion scenario, the displacement-time graph typically takes the shape of a sine or cosine wave, reflecting the periodic nature of the motion.
3. When analyzing these graphs, points where the curve crosses the time axis represent moments when the object is at its equilibrium position.
4. The maximum and minimum points on the graph correspond to the amplitude of motion, showing how far the object moves away from its rest position.
5. Displacement-time graphs can be used to predict future positions of an object in simple harmonic motion by analyzing the pattern of movement.

Review Questions

• How can you determine an object's velocity from a displacement-time graph?
  • Velocity can be determined from the slope of a displacement-time graph. A positive slope indicates that the object is moving away from its starting point, while a negative slope shows it's moving back toward it. The steeper the slope, the greater the speed. If the slope is zero, this means the object is momentarily at rest.
• What does it mean when a displacement-time graph crosses the time axis, and how does this relate to simple harmonic motion?
  • When a displacement-time graph crosses the time axis, it indicates that the object is at its equilibrium position, meaning it has returned to its starting point. In simple harmonic motion, this crossing occurs periodically as the object oscillates back and forth. This periodic crossing reflects the object's continuous movement through maximum and minimum displacements.
• Evaluate how changes in amplitude affect a displacement-time graph in simple harmonic motion.
  • Changes in amplitude will directly affect the height of the peaks and valleys on a displacement-time graph. A larger amplitude results in taller peaks and deeper troughs, indicating greater maximum displacements from equilibrium. This change will not affect the period or frequency unless additional forces are applied but visually alters how pronounced the oscillations appear on the graph. Analyzing these shifts helps understand variations in energy within simple harmonic motion.

Related terms

Amplitude: The maximum extent of displacement from the equilibrium position in simple harmonic motion.

Period: The time taken for one complete cycle of motion in simple harmonic motion, indicating how long it takes to return to the same point.

Frequency: The number of complete cycles of motion that occur in a unit of time, often expressed in Hertz (Hz).