Question

Name the physical quantity which we get from a S-t graph.

Answer 1

Velocity:

1. We get velocity from the slope of the distance-time graph.
2. Velocity is the speed in a particular direction, and it is typically measured in meters per second ($m/sorm{s}^{-1}$).
3. The difference between velocity and speed can be illustrated by a person walking around in a circle at a constant speed of $2$ meters per second.
4. Velocity is a vector quantity; it has both magnitude and direction.

S-t graph (distance-time graph):

1. Speed-Time graphs look much like Distance-Time graphs.
2. Time is plotted on the X-axis. Speed is plotted on the Y-axis.
3. A straight horizontal line on a speed-time graph means the speed is constant throughout.
4. This means that the speed is not changing over time.
5. If we want to find the speed at any particular time, simply draw a vertical line from the x-axis. see where it meets the graph and from that intersection, draw horizontal to the y-axis.
6. That point, where it cuts the y-axis is the required speed. In this way, we can find the speed at any instant as shown above in the figure.
7. When we keep acceleration as a constant, and the initial speed is zero, then speed will increase linearly, as given by the equation below:

$v=u+at$, Since $u=0$, then $v=at$

A positive slope shows an increasing speed. The moving object is accelerating.

A negative slope shows a decreasing speed The moving object is decelerating.

The slope of the S-t graph is speed or velocity.

Hence, we get velocity from the S-t graph.