JEE Main · 2023 · 30 Jan 2023 · Shift 1 · Kinematics

Velocity is the slope of the position-time graph. The curve that steepens as it rises has a velocity that is positive and growing, which pairs with the straight line of velocity increasing from zero. The decaying curve settling toward a fixed position has a negative slope whose magnitude fades to zero, pairing with the velocity that climbs from $-v_0$ toward zero. The triangular track rises at a constant positive slope and then descends at a constant negative slope, pairing with the velocity that jumps from $+v$ to $-v$. The straight sloping line has a constant slope, pairing with the horizontal constant velocity. Thus the first track goes with the uniformly increasing velocity, the decaying one with the velocity approaching zero from below, the triangular one with the velocity that reverses sign, and the straight line with the constant velocity.