Momentum Conservation in Collision?

📌 CONCEPT: In a perfectly inelastic collision, the two colliding objects stick together and move as a single object after collision.

📐 RULE / FORMULA: The law of conservation of momentum applies to inelastic collisions, which states that the total initial momentum of the system remains equal to the total final momentum of the system. The formula is m1u1 + m2u2 = (m1 + m2)v,

💡 WORKED EXAMPLE: In this case, particle 1 is 5 kg and u1 = 2 m/s east, and particle 2 is 3 kg and u2 = -3 m/s (west). Using the formula m1u1 + m2u2 = (m1 + m2)v, we can find the final velocity v. Substituting the given values, 5 * 2 + 3 * (-3) = (5 + 3)v, which simplifies to 10 - 9 = 8v. Therefore, v = (1/8) m/s east.

⚠️ COMMON MISTAKE: Students often forget to consider the direction of the velocities, especially when one particle is moving in the opposite direction. This can lead to incorrect calculation of the final velocity.