Choose the correct option for each question. There is only one correct response for each question.
Four objects of same mass having the same nature of surfaces are kept on a table as given in the figures. Which of these objects will resist the maximum when a force is applied, in a horizontal direction, to move them?

Options

A.
B.
C.
D.

Answer

To solve the question regarding which object will resist the maximum when a force is applied horizontally to move them, we will follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Friction**:
- Friction is a force that opposes the relative motion of two surfaces in contact. The frictional force can be calculated using the formula:
\[ F_{\text{friction}} = \mu \cdot N \]
where \( F_{\text{friction}} \) is the frictional force, \( \mu \) is the coefficient of friction, and \( N \) is the normal force.

2. **Identify the Normal Force**:
- The normal force \( N \) acting on an object resting on a horizontal surface is equal to the weight of the object, which can be calculated as:
\[ N = m \cdot g \]
where \( m \) is the mass of the object and \( g \) is the acceleration due to gravity (approximately \( 9.81 \, \text{m/s}^2 \)).

3. **Analyze the Given Objects**:
- We have four objects with the same nature of surfaces and different masses. Let's denote their masses as follows:
- Object A: 20 kg
- Object B: 15 kg
- Object C: 10 kg
- Object D: 5 kg

4. **Calculate the Frictional Force for Each Object**:
- Since the coefficient of friction \( \mu \) is the same for all objects (as they have the same nature of surfaces), we can focus on the mass to determine which object will have the greatest frictional force. The frictional force will be proportional to the mass of the object:
- For Object A: \( F_{\text{friction}} \propto 20 \, \text{kg} \)
- For Object B: \( F_{\text{friction}} \propto 15 \, \text{kg} \)
- For Object C: \( F_{\text{friction}} \propto 10 \, \text{kg} \)
- For Object D: \( F_{\text{friction}} \propto 5 \, \text{kg} \)

5. **Determine the Object with Maximum Resistance**:
- Since the frictional force is directly proportional to the mass, the object with the greatest mass will have the greatest frictional force. Therefore, Object A (20 kg) will resist the maximum when a force is applied to move it.

### Conclusion:
The object that will resist the maximum when a force is applied in a horizontal direction is **Object A (20 kg)**.