Problem

Problem

Two particles are moving along x-axis. Particle-1 is 40 m behind particle-2. Particle-1 starts with velocity 12 m/s and acceleration 4 m/s2 both in positive x-direction. Particle-2 starts with velocity 4 m/s and acceleration 12 m/s2 also in positive x-direction. Find (a) the time when distance between them is minimum. (b) the minimum distance between them.
Intuitive explanation

This is a relative motion problem where you need to track when (or if) the faster-accelerating particle catches up. The key insight is to write position equations for both particles and find when they're equal—but notice that particle-1 starts faster while particle-2 accelerates harder, so their relative speed changes over time. Set up x1(t)=x2(t)x_1(t) = x_2(t) and solve for tt; you may find multiple solutions (or none), each telling you something about their motion.

Intuitive explanation

This is a relative motion problem where you need to track when (or if) the faster-accelerating particle catches up. The key insight is to write position equations for both particles and find when they're equal—but notice that particle-1 starts faster while particle-2 accelerates harder, so their relative speed changes over time. Set up x1(t)=x2(t)x_1(t) = x_2(t) and solve for tt; you may find multiple solutions (or none), each telling you something about their motion.

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