A man of mass 50 kg carries a bag of weright 40 N on his shoulder. The force with which the floor pushes up his feet will be -

Options

A. 882 N
B. 530 N
C. 90 N
D. 600 N

Answer

To solve the problem, we need to calculate the total force exerted by the man and the bag on the floor, which is equivalent to the normal force exerted by the floor on the man.

### Step-by-Step Solution:

1. **Identify the mass of the man and the weight of the bag**:
- Mass of the man (m) = 50 kg
- Weight of the bag (W_bag) = 40 N

2. **Calculate the weight of the man**:
- The weight of the man (W_man) can be calculated using the formula:
\[ W_{\text{man}} = m \cdot g \]
- Where \( g \) (acceleration due to gravity) is approximately \( 9.8 \, \text{m/s}^2 \).
- Therefore:
\[ W_{\text{man}} = 50 \, \text{kg} \cdot 9.8 \, \text{m/s}^2 = 490 \, \text{N} \]

3. **Calculate the total weight acting downwards**:
- The total weight (W_total) acting downwards on the floor is the sum of the weight of the man and the weight of the bag:
\[ W_{\text{total}} = W_{\text{man}} + W_{\text{bag}} = 490 \, \text{N} + 40 \, \text{N} = 530 \, \text{N} \]

4. **Determine the normal force exerted by the floor**:
- According to Newton's third law, the normal force (N) exerted by the floor on the man will be equal in magnitude and opposite in direction to the total weight acting downwards:
\[ N = W_{\text{total}} = 530 \, \text{N} \]

5. **Conclusion**:
- The force with which the floor pushes up on the man's feet is **530 N**.

### Final Answer:
The force with which the floor pushes up on his feet is **530 N**.

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