Std 11, Physics, Graph 02
Application of Slope
(No. 16)

The position time graph, this is position time graph A, B and C. And it is given that this is a parabola. If it is a parabola, acceleration will be constant. I will explain you why it is. Acceleration will be constant. And if it is upward opening parabola, acceleration will be positive and constant. So, for upward opening parabola, if position time graph is upward opening parabola, acceleration will be positive and constant.
So for entire motion from A to B and from B to C, for the complete motion acceleration is positive and constant. So for this section I will say A is positive and for this section I will say that A is positive. So for upward opening parabola, acceleration will be positive and constant. Any doubt?
Now listen carefully. A to B what about the velocity, will it be negative or positive, negative or positive, how is that defined? Slope of the tangent, greater than 90, tan theta negative. So during this reason v is negative and what about B to C, velocity is positive.
Now listen class, very carefully, B to C both velocity and accelerations are having the same signs that means particle is accelerating and velocity and acceleration are having the opposite sign that means particle is retarding. A to B particle is retarding and B to C particle is accelerating. Any doubt? Listen carefully, let’s discuss one important point.