Speed-time and Distance-time Graphs

Speed-time and Distance-time Graphs

Speed-time Graphs

• Speed-time graphs plot speed on the y-axis and time on the x-axis and illustrate the rate of change of speed with time.

Characteristics

• The gradient of a speed-time graph indicates acceleration. A steeper gradient means greater acceleration.
• A horizontal line indicates constant speed or zero acceleration.
• If the line slopes downwards, it indicates deceleration or slowing down.
• The area under the graph represents the total distance travelled.

Distance-time Graphs

• Distance-time graphs plot distance on the y-axis and time on the x-axis and give an overview of the motion of the object over time.

Characteristics

• The gradient of a distance-time graph shows speed. A steeper gradient implies faster speed.
• A horizontal line represents a stationary object — no change in distance means the object isn’t moving.
• The steeper the graph, the faster the speed of the object.
• A downward sloping line would imply the object is returning to the start.

Interpreting Graphs

• Given a speed-time or distance-time graph, one should be able to interpret the motion of the object, calculate distances, speeds, and accelerations, and potentially even draw similar graphs.

Equations

• The formula to calculate speed from a distance-time graph is given as Speed = Distance ÷ Time.
• The formula to calculate acceleration from a speed-time graph is given as Acceleration = Change in Velocity ÷ Time.
• The formula to calculate distance from a speed-time graph is gotten by calculating the Area under the graph.