Force And Motion – Session 3

A distance time graph shows the relationship between the distance that the object travels and the time it takes to cover that distance. Distance is plotted on the vertical axis. Distance is taken in meters. As you can see at every point the distance is changing by ten meters. Time is taken on the horizontal axis. Time is measured in seconds. At every point the time is changing by one second.

Can you tell what the red point on this graph represents? The red point represents that the object has covered a fourty meters of distance in four seconds. Similarly we can also draw the points on the graph to represent the distance covered by an object.

Let us try to draw the distance time graph when the object is at rest. When the object is at rest, it means it is not moving. Its position does not change with time. To draw the points on a graph we need the values for distance and time. At rest, the object covers zero meters of distance every second. The values for distance and time are given in the table. As you can see, we have drawn all points according to the data of distance and time given in the table.

Can you tell how the distance time graph of an object will look like if the object is moving at constant speed? If the object is moving at a constant speed, it means it is covering the same amount of distance in equal intervals of time. Suppose the object is covering ten meters of distance after every second. This means after one second, the object has covered ten meters of distance. After two seconds it has covered twenty meters of distance. After three seconds, the object has covered thirty meters of distance. The distance and time values for the object moving at constant speed is given in the table.

Now let us draw the points on the graph. First point is drawn at ten meters of distance at one second of time. Second point is drawn at twenty meters at two seconds. Third point is drawn at thirty meters at three seconds. In same way we shall draw the remaining points.

When the object is accelerating, that means it is speeding with the passage of the time. During acceleration, the distance covered by the object in each second increases. For example, the object covers two meters of distance in a second. In the next second, it has covered four meters of distance. In the next second after that, the object has covered six meters of distance. You can see the distance covered by the object in one second increases with the passage of time. We shall now draw the points on graph according to the data of distance and time.

Let us compare the distance time graphs for an object moving at constant speed and the accelerating object. Both graphs are different from each other. The points on the distance time graph of the object at constant speed look like a straight-line. Compare that to the other. The points on the distance time graph of the accelerating object looks like a curved line.

What if the speed of the object is decreasing with time. What will be the distance time graph of the object in this case? In this case, the distance covered by the object is decreasing more and more after each second. For example, the object has covered sixteen meters of distance in first second. In the next second, it has covered fourteen meters of distance. The amount of distance covered by the object in one second is decreasing by two meters. Now we draw the points on the graph according to the data of distance and time given in the table.

A speed time graph is a graphical representation that shows how the speed of an object changes over time. In this graph, the horizontal axis represents the time. The vertical axis represents the speed. We have studied about the distance time graph of the abject at rest. Can you tell what will be the speed time graph of the abject at rest. Is it similar to the distance time graph?.

We know that the speed of the object is zero when it is at rest. The values of speed and time are given for the object at rest. By using these values of speed and time we draw points on the speed time graph.These points shows that the speed of the object is not changing with the time. The object is at rest.

At constant speed, the object covers the same amount of distance in equal intervals of time. This means that the speed of the object remains fixed. It does not change. Suppose the object is moving at constant speed of fifty meters per second. We shall now draw the points on graph by using the data of speed and time. The points on the graph look like a straight-line which is parallel to the horizontal axis. This graph shows that the object is moving at constant speed of fifty meters per second.

When an object undergoes uniform acceleration, it means that its speed is changing at a constant rate over time.Suppose the speed of the object is changing by ten meters per second. After every second the speed increases by ten meters per second. In this case, the value of speed and time are given in the table. We shall now draw the points on the graph according to these values.

When an object undergoes non uniform acceleration, it means its speed is changing at an irregular rate over time. For example, in the first second, the speed increases by three meters per second. In the next second it increases by six meters per second. The speed and time values for the object moving with non uniform acceleration are given in the table. We shall draw the points on the speed time graph according to these values. These points collectively represent the non uniform acceleration.

Let us compare the speed time graph and the distance time graph of the object moving at constant speed.,,. As we can see, the speed time graph is completely different from the distance time graph. The distance time graph appears to be a straight-line that is diagonal starting from the origin. While the points on the speed time graph appear to be a straight-line parallel to the horizontal axis.