Answers
DISTANCE -TIME GRAPHS :
Distance- time graphs shows how the distance of a body from a fixed point changes with time. To draw distance-time graph, distance travelled by the body is plotted along Y-axis and the time taken by the body to travel this distance is plotted along X-axis.
(A) DISTANCE -TIME GRAPH FOR A STATIONARY BODY
The distance of a stationary body from a fixed point does not change with the passage of time. It means, if the distance of a stationary body from a fixed point.
CONCLUSION: Distance- time graph for a stationary body is a straight line (AB) parallel to time-axis.
(B) DISTANCE-TIME GRAPH FOR UNIFORM MOTION
If a body travels equal distances in equal intervals of time, then the motion of the body is known as uniform motion.
CONCLUSION: Distance-time graphs for the uniform motion of a body is a straight line having a constant angle with the time-axis or constant gradient or slope.
(C) DISTANCE-TIME GRAPH FOR NON-UNIFORM MOTION
If a body travels unequal distances in equal intervals of time, then the motion of a body is known as non-uniform motion.
Non-uniform motion of a body is of two types:
1. When the speed of the body increases with passage of time.
For example: when a train leaves the platform, it's speed increases with passage of time. That's is, the train covers more and more distance in unit time.
CONCLUSION: Distance-time graph for the non-uniform motion of a body is a curve having increasing slope or gradient. The speed of such a body changes with time and hence the motion of the body is accelerated.
2. When the speed of the body decreases with passage of time.
For example: when a train approaches the platform, it's speed decreases with the passage of time. That is, the train covers less and less distance in unit time.
CONCLUSION: Distance-time graphs for the decreasing non-uniform motion of a body is a curve having decreasing slope. That is, the speed of the body decreases with passage of time.
