Question

Figure 2-1 6 gives the velocity of a particle moving on an x axis. What

are (a) the initial and (b) the final directions of travel? (c) Does the particle stop momentarily? (d) Is the acceleration positive or negative? (e) Is it constant or varying?

Short answer

(a) The initial direction of travel is negative

(b) The final direction of travel is positive

(c) The particle stops momentarily

(d) The acceleration is positive

(e) The acceleration is constant

Step-by-step solution

Given information

The graph is given in figure 2.16

To understand the concept

From the given graph it can be seen that the initial direction of travel is negative whereas the final direction is positive. When the particle velocity is zero that means the particle stops momentarily. Further, the given graph represents the straight line that is ascending in a positive direction.

(a) Initial direction of travel

The graph starts below the x axis which indicates that the initial direction is negative.

Thus, the initial direction of travel is negative.

(b) Final direction of travel

The graph ends above the x axis which indicates that the final direction is positive.

Thus, the final direction of travel is positive.

(c) Does the particle stop momentarily

From the graph, it is seen that the line crosses the x axis. At that point, the velocity of the particle is zero. When the velocity becomes zero at that moment that means the particle stops momentarily.

(d) Whether the acceleration is positive or negative

the given graph starts from negative velocity to positive velocity which indicates that the velocity is increasing and the slope of v versus t is positive. Thus, the acceleration is positive.

(e) Whether the acceleration is constant or not

As the graph is a straight line, the acceleration is constant.