# Mechanical Engineering - Engineering Mechanics - Discussion

Discussion Forum : Engineering Mechanics - Section 1 (Q.No. 1)
1.
According to principle of conservation of energy, the total momentum of a system of masses in any direction remains constant unless acted upon by an external force in that direction.
True
False
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
94 comments Page 1 of 10.

TADDI APPALA NAIDU said:   3 months ago
False.

The principle you mentioned seems to be a mix-up of two different concepts: the conservation of energy and the conservation of momentum.

The principle of conservation of momentum states that the total momentum of an isolated system of objects remains constant if no external forces act on it. This means that in the absence of external forces, the total momentum of the system in any direction remains the same.

The conservation of energy, on the other hand, states that the total energy of an isolated system remains constant over time, and energy can be transferred or transformed but not created or destroyed.

So, the correct statement would be: According to the principle of conservation of momentum, the total momentum of a system of masses in any direction remains constant unless acted upon by an external force in that direction.
(4)

SRIKANT KUMAR said:   5 months ago
The principle of Conservation of energy is the 1st Law of thermodynamics.
(5)

Dylan Dominguez said:   8 months ago
Thanks all for giving explanations.

Jalesh Kumar Thakur said:   10 months ago
I think the given Statement is not correct.

There should be momentum conservation. And according to the principle of conservation of momentum, the total momentum of a system of masses in any direction remains constant unless acted upon by an external force in that direction.
(2)

Aditya Patki said:   1 year ago
No, the statement is False. The principle of conservation of energy states that the total energy of a closed system is constant, it does not say anything about the momentum of a system of masses. The law of conservation of momentum states that the total momentum of a closed system of masses remains constant unless acted upon by an external force in that direction. So, momentum is conserved, not energy.
(22)

Khan Riyaz Arshad said:   1 year ago
For two or more bodies in an isolated system acting upon each other, their total momentum remains constant unless an external force is applied. Therefore, momentum can neither be created nor destroyed.
(6)

Dipakkumar said:   1 year ago
Momentum is mass x vel.. When the force applied in any direction or here in that direction, energy is added & velocity will increase. so the momentum will increase & hence change.
So the answer should be: True.

Correct me if I am wrong.
(6)

Leela prasad said:   2 years ago
It states that the total amount of energy in an isolated system remains constant over time. The total energy is said to be conserved over time. For an isolated system, this law means that energy can change its location within the system, and that it can change form within the system, for instance chemical energy can become kinetic energy, but that energy can be neither created nor destroyed.
(1)

BADATYA KRISHNA CHANDRA said:   2 years ago
Law of energy says that : Energy can neither created nor destroyed but it can transfer from one form energy.
(3)

Tarun Kumar Singh said:   2 years ago
True, when no change in momentum takes place either we say statically condition.

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