Conservation of momentum in a collision between particles can be understood from

Options

A. conservation of energy
B. Newton's first law only
C. Newton's second law only
D. both Newton's second and third law

Explanation

To understand the conservation of momentum in a collision between particles, we can break down the explanation into a series of steps:

### Step-by-Step Solution:

1. **Understanding Momentum**:
Momentum (P) is defined as the product of mass (m) and velocity (v) of an object, given by the formula \( P = mv \).

2. **Newton's Second Law**:
According to Newton's second law, the net external force (F) acting on a system is equal to the rate of change of momentum. Mathematically, this is expressed as:
\[ F_{\text{external}} = \frac{dP}{dt} \]

3. **Condition for Conservation**:
If the net external force acting on a system is zero (\( F_{\text{external}} = 0 \)), then the change in momentum (\( \frac{dP}{dt} \)) is also zero. This implies that the momentum of the system remains constant:
\[ P = \text{constant} \]

4. **Collisions and Forces**:
In the case of a collision between two particles, the forces they exert on each other are equal in magnitude and opposite in direction, as stated by Newton's third law. This means that while individual particles experience forces, the total force acting on the system of both particles is zero.

5. **Conclusion**:
Since the total external force on the system of particles is zero during the collision, the total momentum of the system before the collision is equal to the total momentum after the collision. This is the principle of conservation of momentum.

### Final Statement:
Thus, the conservation of momentum in a collision between particles can be understood from the fact that if no external forces act on a system, the total momentum of that system remains constant.

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