Laws of MotionNEET MCQs with solutions
Laws of Motion covers Newton's three laws, free-body diagrams, friction (static and kinetic), circular motion dynamics and connected bodies. NEET tests FBD-based problems, friction calculations, motion on inclined planes and problems involving pulleys and strings. Drawing correct FBDs is the key skill.
- Class
- 11 Physics
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- 24 questions
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- 613 questions
- ELITE questions
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- NCERT topics
- 10
Practise 24 questions
Tap an option to check it. Questions from every NCERT topic in this chapter, from easy to hard.
Q1Friction
A book rests on a table. A horizontal force of 5 N is applied but the book does not move. The friction force acting on the book is:
Not quite — the answer is A.
Static friction acts since the book remains at rest. It self-adjusts to exactly balance 5 N, confirming the applied force is below the limiting value. Kinetic friction acts only after sliding begins.
Q2Friction
The maximum value of static friction is called:
Not quite — the answer is C.
Limiting friction is the maximum value static friction can attain, occurring just at the verge of motion. Beyond this value, the body begins to slide and kinetic friction takes over.
Q3Dynamics of Connected Bodies
Two blocks connected by a light inextensible string are pulled on a smooth horizontal surface by an external force. Which quantity is the same for both blocks at every instant?
Not quite — the answer is C.
The inextensible string constraint forces identical displacement at all times, so both blocks share the same acceleration. Net force differs because F=ma and masses differ. Kinetic energy also differs since KE depends on mass.
Q4Dynamics of Connected Bodies
Two blocks of masses 5 kg and 3 kg are connected by a light string on a smooth horizontal surface. A force of 40 N is applied to the 5 kg block. The tension in the string pulling the 3 kg block is:
Not quite — the answer is B.
System acceleration = 40/8 = 5 m/s². Tension acts only on the 3 kg block: T = 3×5 = 15 N. Option C (20 N) arises from incorrectly using total mass ratio instead of only the pulled block's mass.
Q5Newton's Laws of Motion
According to Newton's First Law, a body continues in its state of rest or uniform straight-line motion unless acted upon by:
Not quite — the answer is A.
Newton's First Law requires a non-zero net (unbalanced) external force to change the state of motion. Balanced forces produce zero resultant and cause no change. Gravity alone does not always produce motion change if balanced by normal force.
Q6Newton's Laws of Motion
A body of mass 4 kg experiences a net force of 20 N. Its acceleration is:
Not quite — the answer is B.
By Newton's Second Law, a = F/m = 20/4 = 5 m/s². Option A (2 m/s²) arises from dividing force by 10; Option D (80 m/s²) from multiplying force and mass instead of dividing.
Q7Types of Forces
Which one of the following is a non-contact force?
Not quite — the answer is D.
Gravitational force acts at a distance without physical contact. Friction, tension, and normal reaction arise only when objects are in physical contact.
Q8Types of Forces
Tension in a light inextensible string arises primarily due to which of the following?
Not quite — the answer is B.
Tension arises from intermolecular cohesive forces resisting elongation. It is not an external gravitational, magnetic, or electrostatic interaction.
Q9Pseudo Force and Non-Inertial Frames
A pseudo force is experienced only in:
Not quite — the answer is B.
Pseudo force appears only in accelerating (non-inertial) frames to preserve the form of Newton's second law. Inertial frames and constant-velocity frames need no such correction — Newton's laws hold directly.
Q10Pseudo Force and Non-Inertial Frames
A bus accelerates forward. As observed from inside the bus (non-inertial frame), a standing passenger appears to be pushed backward because:
Not quite — the answer is C.
In the non-inertial bus frame, a pseudo force of magnitude ma acts on every object opposite to the frame's acceleration — here, backward. No real backward force exists; this is purely a fictitious correction for the accelerating frame.
Q11Free Body Diagram (FBD)
A Free Body Diagram (FBD) of an object is drawn to represent:
Not quite — the answer is A.
An FBD shows every external force on the isolated body. Internal forces between parts of the body are excluded. Option B is wrong — unbalanced forces must also be shown.
Q12Free Body Diagram (FBD)
A block rests on a smooth horizontal surface. Which forces must appear in its FBD?
Not quite — the answer is D.
On a smooth surface friction is absent. Weight acts vertically downward and normal reaction acts vertically upward. These two forces balance each other for a block at rest.
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Get RankUp on Google PlayQ13Applications of Newton's Laws (Advanced Mixed Concepts)
A monkey of mass m climbs a light rope with constant speed. The tension in the rope is:
Not quite — the answer is B.
Constant speed means zero acceleration. Applying Newton's Second Law: T − mg = 0, so T = mg. Zero tension is wrong — that occurs only in free fall.
Q14Applications of Newton's Laws (Advanced Mixed Concepts)
A block rests on a rough horizontal surface. A horizontal force is gradually increased from zero. Which quantity begins to change as soon as the force is applied?
Not quite — the answer is C.
Static friction is self-adjusting and immediately matches the applied force (up to μₛN). Normal reaction, kinetic friction, and weight are unaffected until the block begins to move.
Q15Grand Test
A 4 kg block is pulled on a rough horizontal surface (μ = 0.25) by a force of 40 N at 37° above the horizontal. Take g = 10 m/s², sin 37° = 0.6, cos 37° = 0.8. The acceleration of the block is:
Not quite — the answer is C.
Horizontal pull = 40×0.8 = 32 N. N = mg − F sinθ = 40 − 24 = 16 N. Friction = 0.25×16 = 4 N. Net force = 32 − 4 = 28 N. a = 28/4 = 7 m/s² exactly. Trap: using N = mg = 40 N gives friction = 10 N, net = 22 N, a = 5.5 m/s².
Q16Grand Test
A 6 kg block rests on a rough inclined surface (μₛ = 0.5, θ = 30°). Take g = 10 m/s², sin 30° = 0.5, cos 30° = 0.87. The block will:
Not quite — the answer is B.
Down-slope force = mg sinθ = 6×10×0.5 = 30 N. Normal reaction N = mg cosθ = 6×10×0.87 = 52.2 N, so maximum static friction = μₛN = 0.5×52.2 = 26.1 N. Since 30 N > 26.1 N, friction cannot hold the block and it slides down. Shortcut: the block slides whenever tanθ > μₛ (here 0.577 > 0.5). Trap: using N = mg = 60 N gives friction 30 N and wrongly suggests the block stays at rest.
Q17Force and Fundamental Concepts
Which of the following best defines force according to classical mechanics?
Not quite — the answer is A.
Force is an interaction that changes or tends to change a body's state of rest or uniform motion. It is a vector, not a scalar, measured in newtons, not joules.
Q18Force and Fundamental Concepts
A particle is acted upon by two forces of 15 N east and 20 N west. The net force on the particle is:
Not quite — the answer is B.
Taking east as positive: +15 + (−20) = −5 N, meaning 5 N west. Adding magnitudes (35 N) is wrong — forces are vectors and opposite directions require subtraction.
Q19Circular Motion on Level and Banked Roads
A car moves with uniform speed along a circular track. Which force is responsible for continuously changing its direction of motion?
Not quite — the answer is C.
Circular motion requires a net inward force directed toward the centre — centripetal force. It changes direction of velocity without changing speed. Centrifugal force is a pseudo-force in non-inertial frames only.
Q20Circular Motion on Level and Banked Roads
The direction of centripetal acceleration of a body moving in a horizontal circle is:
Not quite — the answer is B.
Centripetal acceleration is always directed radially inward toward the centre. Option A is wrong — tangential direction is perpendicular to centripetal. Options C and D confuse geometry of circular motion.
Q21Force and Fundamental Concepts
All of the following are vector quantities EXCEPT:
Not quite — the answer is C.
Work is the dot product of force and displacement, yielding a scalar. Force, acceleration, and velocity all have direction and are vectors.
Q22Force and Fundamental Concepts
A body is in translational equilibrium under multiple concurrent forces. Which of the following is necessarily true?
Not quite — the answer is A.
Translational equilibrium requires zero net external force — not zero forces. The body may move with constant velocity. Equal magnitudes only apply to pairs, not all forces.
Q23Force and Fundamental Concepts
Which of the following statements about balanced forces is CORRECT?
Not quite — the answer is D.
Balanced forces cancel to give zero resultant — no acceleration results. A moving body under balanced forces continues at constant velocity; it does not stop. Balanced forces act on the same body, unlike Newton's third law pairs.
Q24Force and Fundamental Concepts
Consider the following statements: I. Force is a vector quantity. II. Force can change the shape of a body. III. A non-zero net force is necessary for acceleration. IV. Every force always changes the speed of a body. How many of the above statements are correct?
Not quite — the answer is B.
Statements I, II, and III are correct. Statement IV is false — centripetal force changes direction, not speed, in uniform circular motion. Three statements are correct.
ELITE question · AIR under 50 level
This chapter has 28 ELITE questions for students aiming at the very top. They are only in the app.
Unlock ELITE questions in the appKey Laws & Concepts
Quick revision: most questions in this chapter test these facts.
| Concept | Key Fact |
|---|---|
| Newton's 2nd law | F = ma; net force determines acceleration, not velocity |
| Newton's 3rd law | Action = −Reaction; forces act on different bodies |
| Static friction | f_s ≤ μ_s N; self-adjusting up to maximum value |
| Kinetic friction | f_k = μ_k N; constant; μ_k < μ_s always |
| Inclined plane | Component along plane = mg sinθ; normal = mg cosθ; friction = μmg cosθ |
| Circular motion | Net inward force = mv²/r; banking: tanθ = v²/rg (frictionless) |
What the app covers in this chapter
613 questions in total, each with a detailed explanation.
| Friction | 100 |
| Dynamics of Connected Bodies | 78 |
| Newton's Laws of Motion | 60 |
| Types of Forces | 60 |
| Pseudo Force and Non-Inertial Frames | 60 |
| Free Body Diagram (FBD) | 59 |
| Applications of Newton's Laws (Advanced Mixed Concepts) | 59 |
| Grand Test | 57 |
| Force and Fundamental Concepts | 40 |
| Circular Motion on Level and Banked Roads | 40 |
Questions students ask
Is Laws of Motion important for NEET?
Very important — FBD-based problems, friction numericals and inclined plane questions appear every year. It is one of the highest-weightage Physics chapters.
Which topics should I revise first?
Focus on drawing free-body diagrams correctly, friction (static vs kinetic with calculations), motion on inclined planes, pulley problems, and banking of roads.
How many questions from this chapter are on RankUp?
The RankUp app has 613 questions on Laws of Motion, including 28 ELITE questions. Every question has a detailed explanation.
