A student unable to answer a question on Newton's laws of motion attempts to pull himself up by tugging on her hair. He will not succeed.

Options

A. As the force exerted in small
B. the frictional force while gripping, is small
C. Newton's law of inertia is not applicable to living beings.
D. As the force applied is internal to the system

Answer

To solve the question regarding why a student cannot pull himself up by tugging on his hair, we can analyze the situation using Newton's laws of motion, particularly focusing on the concepts of action and reaction forces.

### Step-by-Step Solution:

1. **Identify the Forces Involved**:
- When the student pulls on his hair, he exerts a force downward on his hair. According to Newton's third law of motion, for every action, there is an equal and opposite reaction. Therefore, the hair exerts an equal force upward on the student's hand.

**Hint**: Remember that action and reaction forces act on different bodies. Here, the action is the force exerted by the student on his hair, and the reaction is the force exerted by the hair on the student's hand.

2. **Analyze the Forces Acting on the Student**:
- The force exerted by the student on his hair (let's call it F) acts downward. Simultaneously, the hair pulls back with an equal force (F) upward on the student's hand.

**Hint**: Consider how forces interact within the same system. The forces acting on the hair and the hand are internal forces.

3. **Net Force Calculation**:
- Since the forces are equal and opposite, the net force acting on the student as a whole is zero. This means the student cannot accelerate upward because there is no unbalanced force acting in that direction.

**Hint**: Recall that for an object to accelerate, there must be a net force acting on it. If the net force is zero, the object will not move.

4. **Conclusion**:
- Because the student is pulling on his hair, both the hand and hair experience equal and opposite forces, resulting in no net force acting on the student. Therefore, he cannot pull himself up.

**Hint**: Think about the implications of Newton's first law (the law of inertia) — an object at rest will stay at rest unless acted upon by a net external force.

### Final Answer:
The student will not succeed in pulling himself up by tugging on his hair because the forces involved are internal to the system, resulting in a net force of zero. Thus, he cannot generate an upward acceleration.