Question

Which of the following is/are correct about conservative and non-conservative forces?
(A) For conservative and non-conservative forces conservation of energy holds good.
(B) Friction is a conservative force.
(C) The work done by a conservative force in a closed path is zero.
(D) Friction is a non-conservative force.
Choose the correct answer from the options given below:

• A. (A), (C) and (D) only
• B. (A), (B) and (C) only
• C. (A), (B) and (D) only
• D. (B), (C) and (D) only

Hint:

Key distinctions to remember:
{Conservative Force}: Work is path-independent; work in a closed loop is zero; mechanical energy is conserved. Examples: Gravity, electrostatic force, ideal spring force.
{Non-Conservative Force}: Work is path-dependent; work in a closed loop is not zero; mechanical energy is dissipated. Examples: Friction, air resistance, viscous drag.
The Law of Conservation of *Total* Energy always holds.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
This question tests the fundamental definitions and properties of conservative and non-conservative forces in physics.
Step 2: Detailed Explanation:
Let's analyze each statement:

(A) For conservative and non-conservative forces conservation of energy holds good. This statement is true. The law of conservation of total energy is a universal principle. For conservative forces, mechanical energy (Kinetic + Potential) is conserved. For non-conservative forces, mechanical energy is not conserved, but it is converted into other forms of energy (like heat due to friction). The total energy of an isolated system is always conserved, regardless of the nature of the internal forces.

(B) Friction is a conservative force. This is false. Friction is a classic example of a non-conservative force. The work done by friction depends on the path taken and it dissipates mechanical energy.

(C) The work done by a conservative force in a closed path is zero. This is a fundamental definition of a conservative force. If a particle moves around any closed loop and returns to its starting point, the net work done by a conservative force (like gravity or an ideal spring force) is zero.

(D) Friction is a non-conservative force. This is true. As explained for statement (B), friction is a dissipative, path-dependent force and is therefore non-conservative.
Step 3: Final Answer:
Statements (A), (C), and (D) are correct. Statement (B) is incorrect. Therefore, the correct option includes (A), (C), and (D).