Question

1. velocity - time graph sketch a b - time graph for a car that goes east at 25 m/s for 100 s, then west at 25 m/s for another 100 s. figure 10

Explanation:

Step1: Set up axes

Let the x - axis be time (in s) and the y - axis be velocity (in m/s).

Step2: First part of motion

For the first 100 s, the car moves east at 25 m/s. On the velocity - time graph, this is a horizontal line at $v = 25$ m/s from $t = 0$ s to $t=100$ s.

Step3: Second part of motion

Then it moves west at 25 m/s for another 100 s. Since west is the opposite direction of east, the velocity is negative. So, from $t = 100$ s to $t = 200$ s, there is a horizontal line at $v=- 25$ m/s.

To sketch:

1. Draw the x - axis (time) and label it from 0 to 200 s with an appropriate scale.
2. Draw the y - axis (velocity) and label it with positive values for east - direction velocities and negative values for west - direction velocities.
3. Draw a horizontal line at $y = 25$ from $x = 0$ to $x = 100$.
4. Draw a horizontal line at $y=-25$ from $x = 100$ to $x = 200$.

Answer:

Sketch a horizontal line at $v = 25$ m/s from $t = 0$ s to $t = 100$ s and a horizontal line at $v=-25$ m/s from $t = 100$ s to $t = 200$ s on a velocity - time graph.