The given figure shows the displacement−time graph of a particle.

Which of the following statements about the motion of the particle is definitely correct?

Velocity is defined as the rate of change of displacement. In a position−time graph, velocity is measured by the slope of the position−time line. In the given graph, the slope of the position−time line is constant up to time t₁. Therefore, the velocity of the particle is constant up to time t₁. After that, no displacement of the particle occurs. Therefore, the velocity of the particle becomes zero i.e., the particle stops after time t₁.

The correct answer is A.

Why alternative B is wrong:

Since the position−time graph of the particle is a straight line up to time t₁, the velocity is constant during this time period. It is not decreasing.

Why alternative C is wrong:

From the given graph, nothing can be said about the initial velocity of the particle. From the graph, the only interpretation that can be made about initial state of the particle is that it starts with some initial displacement.

Why alternative D is wrong:

The final velocity of the particle is 0.