Assertion: A man who falls from aheight on a cement floor receive more injury than when he falls from the same height on a heap of sand.
Reason: The impulse applied by a cement floor is more than the impulse by sand floor.

Options

A. If both assertion `&` Reason are True `&` the Reason is a corrrect explanation of the Asserion.
B. If both Assertion `&` Reason are True but Reason is not correct explanation of the Assertion.
C. If Assertion is Trie but the Reason is False.
D. If both Assertion `&` Reason are false

Explanation

To solve the question, we need to analyze the assertion and reason provided:

**Assertion:** A man who falls from a height on a cement floor receives more injury than when he falls from the same height on a heap of sand.

**Reason:** The impulse applied by a cement floor is more than the impulse by sand floor.

### Step-by-Step Solution:

1. **Understanding Impulse:**
- Impulse is defined as the change in momentum of an object when a force is applied over a period of time. Mathematically, impulse (J) can be expressed as:
\[ J = F \cdot \Delta t \]
- Where \( F \) is the average force applied, and \( \Delta t \) is the time duration over which the force acts.

2. **Analyzing the Fall:**
- When a man falls from a height, he gains velocity due to gravity. Upon hitting the ground, he experiences a force that brings him to rest.
- The change in momentum (Δp) is the same in both cases (falling onto cement or sand) since he falls from the same height.

3. **Time of Contact:**
- When the man falls onto a cement floor, the time of contact (\( \Delta t_1 \)) is very short because the cement is a hard surface.
- Conversely, when he falls onto a heap of sand, the time of contact (\( \Delta t_2 \)) is longer because the sand compresses and allows for a gradual deceleration.

4. **Comparing Forces:**
- Since the impulse must be equal in both cases (the change in momentum is the same), we can set up the following relationship:
\[ J = F_1 \cdot \Delta t_1 = F_2 \cdot \Delta t_2 \]
- Rearranging gives us:
\[ F_1 = \frac{J}{\Delta t_1} \quad \text{and} \quad F_2 = \frac{J}{\Delta t_2} \]
- Since \( \Delta t_1 < \Delta t_2 \), it follows that \( F_1 > F_2 \). This means the average force exerted on the man when he hits the cement is greater than that when he hits the sand.

5. **Conclusion:**
- The greater force (impulse) experienced on the cement floor results in more severe injuries compared to the sand, which absorbs more energy and reduces the force experienced by the man.
- Therefore, both the assertion and the reason are true, and the reason correctly explains the assertion.

### Final Answer:
The assertion is true, and the reason is also true. The reason is the correct explanation for the assertion.