Correct Option
The correct option is (c).
Explanation
The Newton's First and Second Laws of Motion. Newton's Second Law relates force, mass, and acceleration through the equation $F_{net} = ma$. Newton's First Law (Law of Inertia) states that an object will remain in its state of rest or uniform motion unless acted upon by a net unbalanced external force.
Statement-wise Analysis
- Statement 1 is Correct: If the net unbalanced external force is zero ($F_{net} = 0$), the acceleration is zero ($a = 0$). This means the object's velocity remains constant. If the object was initially stationary, it will remain at rest.
- Statement 2 is Incorrect: Non-uniform velocity implies that the velocity is changing in magnitude (speed) or direction. Any change in velocity represents acceleration ($a \neq 0$). However, since the net force is zero, acceleration must be zero. Therefore, the object cannot move with non-uniform velocity.
- Statement 3 is Correct: According to the relationship $F_{net} = ma$, if the net external force is zero, the acceleration of the object must be zero. This is the condition for translational equilibrium.
Key Takeaway: When the net external force on an object is zero, the object is in a state of equilibrium. This implies zero acceleration, meaning the object is either at rest or moving with a constant velocity.