NEET Physics: Newton’s Second Law of motion Practice Questions
13 free multiple-choice questions on Newton’s Second Law of motion (Laws of Motion) for NEET Physics, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more NEET questions in the app →Q1. If the mass of an object is halved and the same net force is applied, the resulting acceleration will be:
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Correct answer: B — Doubled
Since acceleration is inversely proportional to mass (a=F/m), if the mass is halved while the force remains the same, the acceleration will be doubled (a = F/(m/2) = 2F/m).
Q2. Newton's Second Law states that the acceleration of an object is directly proportional to the net force applied to it, provided the mass remains constant. Which of the following is true?
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Correct answer: B — Acceleration is directly proportional to the net force.
The mathematical form of the second law is a = F/m. This clearly shows that acceleration (a) is directly proportional to the net force (F) when mass (m) is constant.
Q3. If the mass of an object is m and the acceleration of the object is a, what is the expression for the net force applied to it?
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Correct answer: B — m × a
From Newton's Second Law, F = ma. Therefore, the net force is the product of the mass and the acceleration.
Q4. If a constant force acts on an object, and its mass is doubled, what will be the resulting acceleration?
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Correct answer: A — The acceleration will be doubled
According to Newton's Second Law (F=ma), if the force (F) remains constant and the mass (m) is doubled, the acceleration (a) must be halved (a = F/2m).
Q5. A body moving in a straight line has a constant acceleration. This implies that the net force acting on the body is:
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Correct answer: B — Constant
Since acceleration is constant, and F=ma, the net force (F) must also be constant (assuming mass is constant).
Q6. If the net external force acting on an object is doubled, and its mass remains unchanged, how will its acceleration change?
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Correct answer: B — It will be doubled
Since acceleration (a) is directly proportional to the net force (F) when mass (m) is constant (a = F/m), if F is doubled, a will also be doubled.
Q7. A book of mass 5 kg is pulled with a force of 20 N. What is the acceleration produced in the book? (Assume no friction)
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Correct answer: D — 4 m/s²
Using F = ma, we have a = F/m. a = 20 N / 5 kg = 4 m/s².
Q8. Which physical quantity is the SI unit of force?
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Correct answer: B — Newton
The SI unit of force is the Newton (N). Since Force = mass × acceleration (F=ma), the unit is kg · m/s², which is defined as the Newton.
Q9. Newton's Second Law is mathematically expressed as:
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Correct answer: C — F = ma
The fundamental mathematical statement of Newton's Second Law relates the net force (F) acting on an object to its mass (m) and the resulting acceleration (a) via the equation F = ma.
Q10. If a constant force acts on an object, the resulting acceleration is inversely proportional to the object's:
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Correct answer: D — Mass
The formula is F = ma, which means a = F/m. If the force (F) is constant, acceleration (a) is inversely proportional to the mass (m).
Q11. If the acceleration of an object is zero, the net force acting on the object must be:
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Correct answer: D — Zero
Since F = ma, if acceleration (a) is zero, the net force (F) acting on the body must also be zero.
Q12. An object moves with a constant velocity. What is the net force acting on the object?
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Correct answer: A — The net force is always zero
According to Newton's First Law (which is a consequence of the Second Law), if an object moves with constant velocity (zero acceleration), the net external force acting on it must be zero (ΣF = 0).
Q13. If the mass of an object is increased while keeping the net force applied constant, what happens to its acceleration?
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Correct answer: A — Acceleration decreases
Since acceleration is inversely proportional to mass (a=F/m), if the mass (m) is increased while the force (F) is constant, the resulting acceleration (a) must decrease.
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