In an inelastic collision I. Energy is conserved II. Energy is decreased III. Energy is increased IV. Linear momentum conserved

Analysis of the Question

This question tests your understanding of the laws of conservation in physics, specifically regarding collisions. You need to distinguish between elastic and inelastic collisions.

Concept Explanation

1. Linear Momentum: According to the Law of Conservation of Linear Momentum, the total momentum of a system remains constant in any collision (whether elastic or inelastic), provided no external force acts on the system.
2. Kinetic Energy: • In an elastic collision, both linear momentum and kinetic energy are conserved. • In an inelastic collision, linear momentum is conserved, but kinetic energy is not conserved. Instead, some of the kinetic energy is transformed into other forms of energy (such as heat, sound, or deformation energy). Therefore, the total kinetic energy of the system decreases after the collision.

Step-by-Step Solution

• Step 1: Evaluate Statement I ("Energy is conserved"). This is false for inelastic collisions because kinetic energy is lost to other forms.
• Step 2: Evaluate Statement II ("Energy is decreased"). This is true. In an inelastic collision, the total kinetic energy after the collision is less than the total kinetic energy before the collision.
• Step 3: Evaluate Statement III ("Energy is increased"). This is false. Energy is not created during a collision; it is only transformed or dissipated.
• Step 4: Evaluate Statement IV ("Linear momentum conserved"). This is true. The principle of conservation of momentum applies to all collisions.

Combining these, statements II and IV are the correct descriptions of an inelastic collision.

Conclusion

Based on the analysis, the correct statements are II and IV. This corresponds to option B.

Exam Tip: Always remember the "Golden Rule" of collisions: Momentum is always conserved, but Kinetic Energy is only conserved in elastic collisions. If you see the word "inelastic," immediately look for the option that mentions a decrease in energy!