Consider the following statements : 1. There is no net moment on a body which is in equilibrium. 2. The momentum of a body is always conserved. 3. The kinetic energy of an object is always conserved. Which of the statements given above is/are correct?

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Q: 10 (CDS-I/2018)
Consider the following statements :
1. There is no net moment on a body which is in equilibrium.
2. The momentum of a body is always conserved.
3. The kinetic energy of an object is always conserved.
Which of the statements given above is/are correct?

question_subject: 

Science

question_exam: 

CDS-I

stats: 

0,13,21,8,8,13,5

keywords: 

{'kinetic energy': [0, 0, 4, 7], 'net moment': [0, 0, 0, 1], 'momentum': [0, 1, 0, 3], 'equilibrium': [0, 1, 0, 0], 'body': [27, 3, 23, 37]}

The correct answer is option 3, which states that statements 1 and 2 only are correct. Let`s dissect each statement to understand why this is the correct answer.

Statement 1: "There is no net moment on a body which is in equilibrium." This statement is true. In physics, equilibrium refers to a state where an object`s net force and net torque are both zero. In this state, there is no change in the object`s linear or angular motion, meaning there is no net moment acting on it.

Statement 2: "The momentum of a body is always conserved." This statement is incorrect. Conservation of momentum is a fundamental principle in physics, stating that the total momentum of an isolated system remains constant if no external forces act on it. However, in the presence of external forces, the momentum of a body can change. Therefore, momentum is not always conserved.

Statement 3: "The kinetic energy of an object is always conserved." This statement is also incorrect. Kinetic energy, which is the energy possessed by an object due to its motion, is not always conserved. It can change due to work done by external forces, such as friction or air resistance.

In summary, statement 1 is correct, statement 2