Question

A girl walks along a straight path to drop a letter in the letterbox and comes back to drop a letter in the letter box and comes back to her initial position. Her displacement-time graph is shown in the figure below. Plot a velocity-graph graph for the same.

Answer 1

Step 1: Given diagram

The given displacement-time graph,

Step 2: Analysing and calculating velocity

Velocity is defined as the rate of change of the displacement in a given direction.

For the first $50$seconds of the time interval, the change in displacement is $100$.

$v=\frac{x_f-x_i}{t}=\frac{100-0}{50}=2m{s}^{-1}$

So, the velocity is $2m{s}^{-1}$.

For another $50$seconds of time interval, the change in displacement is $-100$.

$v=\frac{x_f-x_i}{t}=\frac{0-100}{50}=-2m{s}^{-1}$

So, the velocity is $-2m{s}^{-1}$.

Step 3: Plotting the graph:

Hence, the velocity-time graph will be