Assertion: A body is thrown with a velocity u inclined to the horizontal at some angle. It moves along a parabolic path and falls to the ground, Linear momentum of the body, during its motion, will remain conserved.
Reason: Throughout the motion of the body, a constant force acts on it.

Options

A. If both Assertion and Reason are correct and Reason is the correct explanation of Assertion.
B. If both Assertion and Reason are correct but Reason is not the correct explanation of Assertion.
C. If Assertion is true but Reason is false.
D. If Assertion is false but Reason is true.

Answer

To analyze the given assertion and reason, let's break down the concepts step by step:

### Step 1: Understanding the Assertion
The assertion states that a body thrown with an initial velocity \( u \) at an angle to the horizontal will follow a parabolic path and that its linear momentum will remain conserved throughout its motion.

### Step 2: Analyzing the Motion
When a body is thrown at an angle, it experiences projectile motion. In this motion, the body has both horizontal and vertical components of velocity. The horizontal component remains constant because there are no forces acting in that direction (assuming air resistance is negligible). However, the vertical component is affected by gravity.

### Step 3: Forces Acting on the Body
As the body moves, the only force acting on it is the gravitational force acting downward. This force is constant and affects the vertical motion of the body.

### Step 4: Conservation of Linear Momentum
For linear momentum to be conserved, the net external force acting on the system must be zero. In this case, since there is a constant gravitational force acting on the body, the linear momentum of the body is not conserved. The vertical momentum changes due to the gravitational force, even though the horizontal momentum remains constant.

### Step 5: Evaluating the Reason
The reason states that a constant force acts on the body throughout its motion. This is true because the gravitational force is constant. However, the presence of this force means that the linear momentum of the body cannot be conserved.

### Conclusion
Based on the analysis, we conclude:
- The assertion is **false** because the linear momentum is not conserved.
- The reason is **true** because a constant force (gravity) acts on the body.

Thus, the correct answer is that the assertion is false, and the reason is true.

### Final Answer
The assertion is false, and the reason is true.

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