Lesson 4. Flashcards
What does a graph of distance against time mean?
A graph of distance against time tells you about the speed of an object on its journey. The speed is equal to the gradient (or slope) of the graph.
What does a straight line mean?
That the object’s speed is constant.
What does a horizontal line mean?
That the object is not moving.
The steeper the line, the …… the object is travelling.
Faster.
How do you calculate the speed from a graph?
Draw a right-angled triangle under the line. From the triangle, find the change in distance and the change in time. Then, use the equation for speed to find the answer.
How is a distance-time graph different from a displacement-time graph?
A distance-time graph shows the total distance travelled. However, if you plot a displacement-time graph then the gradient can be positive, zero, or negative. The gradient of the graph is the velocity, so it has a direction as well as a magnitude, unlike distance-time graphs.
How do you calculate velocity from a graph?
Draw a right-angled triangle under the line, e.g., between 350s and 900 s, then find the change in displacement and the change in time from the triangle. Use the equation for velocity to find the answer.
