The correct option is (a) 1 only.
Explanation
Newton's Laws of Motion describe the relationship between the motion of an object and the forces acting on it. The First Law defines the concept of inertia, stating that an object remains in its state of rest or uniform motion unless acted upon by an external force. The Second Law provides a quantitative measure of force, relating it to the rate of change of momentum.
Statement-wise Analysis
- Statement 1 is Correct: The Second Law of Motion is mathematically expressed as $F = ma$, where $F$ is the net external force, $m$ is the mass, and $a$ is the acceleration. If no net external force acts on a body, then $F = 0$. Substituting this into the equation gives $ma = 0$. Since mass ($m$) is non-zero, the acceleration ($a$) must be zero. Zero acceleration implies that the velocity remains constant (either the body is at rest or moving with uniform velocity). This conclusion is identical to the statement of the First Law. Therefore, the First Law can be deduced from the Second Law.
- Statement 2 is Incorrect: As established in the analysis of Statement 1, the First Law corresponds to the specific condition within the Second Law where the applied net external force is zero. It is not a case where the force is infinite. An infinite force would result in infinite acceleration (for a finite mass), which contradicts the principle of inertia described in the First Law.
Key Takeaway
Newton's First Law of Motion is effectively a special case of the Second Law ($F = ma$) applicable when the net external force acting on the system is zero ($F_{net} = 0$).