JEE Physics Laws Of Motion MCQs Set 27

Multiple Choice Questions (MCQs) for JEE Physics: Laws Of Motion

Explore reliable objective questions for Laws Of Motion tailored for JEE learners. Utilizing these Physics multiple-choice formats ensures thorough preparation and strengthens problem-solving speed for upcoming school assessments.

Practice Laws Of Motion MCQs for JEE Physics

Access the complete set of multiple-choice questions for Laws Of Motion below. This focused format allows students to isolate specific topics for thorough review and uninterrupted practice alongside official JEE textbooks.

Multiple Choice Questions

Question 1: A bridge is in the form of a semi-circle of radius 40 m. The greatest speed with which a motor cycle can cross the bridge without leaving the ground at the highest point is (g = 10 m/s²) (frictional force is negligibly small)
(a) 40 m/s
(b) 20 m/s
(c) 30 m/s
(d) 15 m/s
Show Answer & Explanation

Answer: (b) 20 m/s

Explanation:
1. At the highest point mg − N = mv²/r.
2. The limit is N = 0, so v = √(gr) = √400 = 20 m/s.

Teacher's Note:
1. The normal force becomes zero at the limit.

Question 2: If μs, μk and μr are the coefficients of static, kinetic and rolling friction, then
(a) \( \mu_s<\mu_k<\mu_r \)
(b) \( \mu_k<\mu_r<\mu_s \)
(c) \( \mu_r<\mu_k<\mu_s \)
(d) \( \mu_r=\mu_k=\mu_s \)
Show Answer & Explanation

Answer: (c) \( \mu_r<\mu_k<\mu_s \)

Explanation:
1. Rolling friction is the smallest, static friction the largest.
2. So μr < μk < μs.

Teacher's Note:
1. Rolling is easier than sliding, and sliding easier than starting.

Question 3: Inertia is the property of a body linked to its tendency
(a) to change its position
(b) to change its direction
(c) to change its momentum
(d) to resist any change in its state
Show Answer & Explanation

Answer: (d) to resist any change in its state

Explanation:
1. Inertia is the ability of a body to oppose any change in its state of rest or of uniform motion.
2. Mass is the measure of inertia.

Teacher's Note:
1. Inertia resists change; it does not cause change.

Question 4: The coefficient of static friction between two surfaces depends upon
(a) the normal reaction
(b) the shape of the surface in contact
(c) the area of contact
(d) none of these
Show Answer & Explanation

Answer: (d) none of these

Explanation:
1. The coefficient depends only on the nature (material and roughness) of the surfaces.
2. It is independent of normal reaction, area and shape.

Teacher's Note:
1. μ is a property of the pair of materials.

Question 5:
Assertion (A): An object can move with constant velocity if no net force acts on it.
Reason (R): No net force is needed to move an object with constant velocity.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
Show Answer & Explanation

Answer: (a) Both A and R are true, and R is the correct explanation of A.

Explanation:
1. By Newton's first law, zero net force gives constant velocity.
2. The Reason states the same fact and explains the Assertion.

Teacher's Note:
1. Motion at constant velocity is a force-free state.

Question 6: Which of the following forces does not act on a body moving in uniform circular motion?
(a) Centripetal force
(b) Weight of the body
(c) Normal reaction
(d) Force of friction
Show Answer & Explanation

Answer: (a) Centripetal force

Explanation:
1. Centripetal force is the resultant of the real forces such as tension, friction or gravity.
2. It is not an extra, separate force acting on the body.

Teacher's Note:
1. Name the actual forces and add them up.

Question 7:
Assertion (A): Mass is a measure of inertia of the body in linear motion.
Reason (R): The greater the mass, the greater the force required to change its state of rest or of uniform motion.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
Show Answer & Explanation

Answer: (a) Both A and R are true, and R is the correct explanation of A.

Explanation:
1. Inertia is the resistance to a change in motion, and the larger the mass, the larger the force needed for a given acceleration.
2. The Reason correctly explains the Assertion.

Teacher's Note:
1. F = ma links mass with resistance to change.

Question 8: A train is moving with a speed of 36 km/h on a curved path of radius 200 m. If the distance between the rails is 1.5 m, the height of the outer rail over the inner rail is (g = 10 m/s²)
(a) 1 m
(b) 0.5 m
(c) 0.75 m
(d) 0.075 m
Show Answer & Explanation

Answer: (d) 0.075 m

Explanation:
1. v = 10 m/s and tan θ = v²/rg = 100/2000 = 0.05.
2. h = l tan θ = 1.5 × 0.05 = 0.075 m.

Teacher's Note:
1. Small angle: h/l ≈ tan θ.

Question 9: If the net external force on a body is ...X..., its acceleration is zero. Acceleration can be ...Y... only if there is a net external force on the body. X and Y refer to
(a) zero, zero
(b) zero, non-zero
(c) non-zero, zero
(d) non-zero, non-zero
Show Answer & Explanation

Answer: (b) zero, non-zero

Explanation:
1. By F = ma, zero net force gives zero acceleration.
2. A non-zero acceleration needs a non-zero net external force.

Teacher's Note:
1. The first law in the language of the second.

Question 10:
Assertion (A): The linear momentum of a body changes even when it is moving uniformly in a circle.
Reason (R): In uniform circular motion, the velocity remains constant.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
Show Answer & Explanation

Answer: (c) A is true, but R is false.

Explanation:
1. The direction of velocity, and hence of momentum, keeps changing, so the Assertion is true.
2. The velocity does not remain constant, so the Reason is false.

Teacher's Note:
1. Momentum is a vector.

Question 11: Select the incorrect statement(s) about static friction. I. Static friction exists on its own. II. In the absence of an applied force, static friction is maximum. III. Static friction is equal and opposite to the applied force up to a certain limit.
(a) I only
(b) II and III
(c) I and III
(d) I and II
Show Answer & Explanation

Answer: (d) I and II

Explanation:
1. Static friction exists only in response to an applied force, so I is incorrect.
2. With no applied force it is zero, not maximum, so II is incorrect.
3. III is correct.

Teacher's Note:
1. Static friction is self-adjusting up to its limit.

Question 12: The same change in momentum about in ...X... time needs ...Y... force applied. X and Y refer to
(a) longer, lesser
(b) shorter, greater
(c) both (a) and (b)
(d) longer, greater
Show Answer & Explanation

Answer: (c) both (a) and (b)

Explanation:
1. F = Δp/Δt for a fixed Δp.
2. A longer time needs a smaller force, and a shorter time needs a greater force, so both pairings are correct.

Teacher's Note:
1. Force and time are inversely related for fixed momentum change.

Question 13: A ball of mass 10 g moving perpendicular to the plane of a wall strikes it and rebounds in the same line with the same velocity. If the impulse experienced by the wall is 0.54 N s, the velocity of the ball is
(a) 27 m/s
(b) 3.7 m/s
(c) 54 m/s
(d) 37 m/s
Show Answer & Explanation

Answer: (a) 27 m/s

Explanation:
1. Impulse = 2mv.
2. v = 0.54/(2 × 0.01) = 27 m/s.

Teacher's Note:
1. The momentum change is 2mv.

Question 14: A spacecraft of mass 100 kg breaks into two parts when its velocity is 10⁴ m/s. After the break, a mass of 10 kg of the spacecraft is left stationary. The velocity of the remaining part is
(a) 10³ m/s
(b) 11.11 × 10³ m/s
(c) 11.11 × 10² m/s
(d) 10⁴ m/s
Show Answer & Explanation

Answer: (b) 11.11 × 10³ m/s

Explanation:
1. Momentum before = 100 × 10⁴.
2. After: 10 × 0 + 90 v.
3. v = 10⁶/90 = 11.11 × 10³ m/s.

Teacher's Note:
1. Conserve linear momentum.

Question 15: If the normal force is doubled, the coefficient of friction is
(a) halved
(b) tripled
(c) doubled
(d) unchanged
Show Answer & Explanation

Answer: (d) unchanged

Explanation:
1. μ depends on the surfaces only.
2. Doubling N doubles the friction, but μ stays the same.

Teacher's Note:
1. μ = f/N is a constant for a given pair of surfaces.

Question 16: An explosion breaks a rock into three parts in a horizontal plane. Two of them go off at right angles to each other. The first part of mass 1 kg moves with a speed of 12 m/s and the second part of mass 2 kg with speed 8 m/s. If the third part flies off with speed 4 m/s, its mass is
(a) 5 kg
(b) 7 kg
(c) 17 kg
(d) 3 kg
Show Answer & Explanation

Answer: (a) 5 kg

Explanation:
1. The momenta of the first two parts are 12 and 16 kg m/s at right angles, giving a resultant √(144 + 256) = 20 kg m/s.
2. The third part must have equal momentum, so m × 4 = 20 and m = 5 kg.

Teacher's Note:
1. Total momentum after the explosion is zero.

Question 17:
Assertion (A): A cricketer moves his hands forward to catch a ball so as to catch it easily without hurting.
Reason (R): He tries to decrease the distance travelled by the ball so that it hurts less.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
Show Answer & Explanation

Answer: (c) A is true, but R is false.

Explanation:
1. Moving the hands back increases the stopping time, which reduces the force, so the Assertion is true.
2. The reason given is wrong because he increases the time (and stopping distance), not decreases it.

Teacher's Note:
1. Longer stopping time means a smaller force.

Question 18:
Assertion (A): Impulse of force and momentum are the same physical quantities.
Reason (R): Both quantities have the same unit.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
Show Answer & Explanation

Answer: (d) A is false, but R is true.

Explanation:
1. Impulse is force × time and momentum is mass × velocity.
2. They have the same dimensions and units but are different quantities, so the Assertion is false and the Reason is true.

Teacher's Note:
1. Same unit does not mean same quantity.

Question 19: China wares are wrapped in straw or paper before packing. This is an application of the concept of
(a) impulse
(b) momentum
(c) acceleration
(d) force
Show Answer & Explanation

Answer: (a) impulse

Explanation:
1. The wrapping increases the time of impact during a jolt.
2. For the same change in momentum, a longer time means a smaller force, so the wares are less likely to break.

Teacher's Note:
1. F = Δp/Δt: increase Δt to reduce F.

Question 20: A block of mass m is placed on a smooth wedge of inclination θ. The whole system is accelerated horizontally so that the block does not slip on the wedge. The force exerted by the wedge on the block (g is the acceleration due to gravity) will be
(a) \( mg/\cos\theta \)
(b) \( mg\cos\theta \)
(c) \( mg\sin\theta \)
(d) mg
Show Answer & Explanation

Answer: (a) \( mg/\cos\theta \)

Explanation:
1. The block has no vertical acceleration, so N cos θ = mg.
2. N = mg/cos θ.

Teacher's Note:
1. Resolve the normal reaction vertically.

Question 21: Which one of the following motions on a smooth plane surface does not involve force?
(a) Accelerated motion in a straight line
(b) Retarded motion in a straight line
(c) Motion with constant motion along a straight line
(d) Motion along a straight line with varying velocity
Show Answer & Explanation

Answer: (c) Motion with constant motion along a straight line

Explanation:
1. Force is needed only when velocity changes.
2. Motion with constant velocity along a straight line needs no force.

Teacher's Note:
1. No change in velocity, no force.

Question 22: A balloon of mass m is descending with an acceleration a (a less than g). How much mass should be removed from it so that it starts moving up with an acceleration a?
(a) \( \frac{2ma}{g+a} \)
(b) \( \frac{2ma}{g-a} \)
(c) \( \frac{ma}{g+a} \)
(d) \( \frac{ma}{g-a} \)
Show Answer & Explanation

Answer: (a) \( \frac{2ma}{g+a} \)

Explanation:
1. Upthrust U: mg − U = ma, so U = m(g − a).
2. After removing Δm: U − (m − Δm)g = (m − Δm)a, so (m − Δm)(g + a) = m(g − a).
3. Δm = 2ma/(g + a).

Teacher's Note:
1. Upthrust remains the same.

Question 23: The upper half of an inclined plane of inclination θ is perfectly smooth while the lower half is rough. A block starting from rest at the top of the plane will again come to rest at the bottom if the coefficient of friction between the block and the lower half is given by
(a) \( \mu=\frac{2}{\tan\theta} \)
(b) \( \mu=2\tan\theta \)
(c) \( \mu=\tan\theta \)
(d) \( \mu=\frac{1}{\tan\theta} \)
Show Answer & Explanation

Answer: (b) \( \mu=2\tan\theta \)

Explanation:
1. Let the length be L. By the work-energy theorem from top to bottom: mgL sin θ − μ mg cos θ (L/2) = 0.
2. So μ = 2 tan θ.

Teacher's Note:
1. Work done by gravity equals work against friction over half the length.

Question 24: Swimming is possible on account of
(a) the first law of motion
(b) the second law of motion
(c) the third law of motion
(d) Newton's law of gravitation
Show Answer & Explanation

Answer: (c) the third law of motion

Explanation:
1. The swimmer pushes the water backward and the water pushes the swimmer forward with an equal and opposite force.
2. This is Newton's third law.

Teacher's Note:
1. Action and reaction act on different bodies.

Question 25: The direction of impulse is
(a) the same as that of the net force
(b) opposite to that of the net force
(c) the same as that of the final velocity
(d) the same as that of the initial velocity
Show Answer & Explanation

Answer: (a) the same as that of the net force

Explanation:
1. Impulse = F Δt with Δt positive.
2. So it points in the direction of the net force, which is the direction of the change in momentum.

Teacher's Note:
1. Time is a positive scalar.

Free study material for Physics

Laws Of Motion Objective Questions & Solutions for JEE Physics

JEE Physics Laws Of Motion Objective Test Questions

Test your conceptual understanding of Laws Of Motion with these targeted multiple-choice questions. Designed in alignment with the latest JEE curriculum for JEE Physics, these problem sets build accuracy and prepare students for objective exams.

NCERT-Aligned Objective Questions and Solutions

Each question includes structured solution keys mapped directly to standard JEE textbooks, helping students evaluate their reasoning and correct mistakes early in their revision.

Next Steps in Your Exam Preparation

Explore our broader library of printable assignments, chapter notes, and mock tests designed to support continuous revision and secure higher marks in JEE assessments.

FAQs

Where can I access latest JEE Physics Laws Of Motion MCQs Set 27?

You can get most exhaustive JEE Physics Laws Of Motion MCQs Set 27 for free on StudiesToday.com. These MCQs for JEE Physics are updated for the 2026-27 academic session as per JEE examination standards.

Are Assertion-Reasoning and Case-Study MCQs included in the Physics JEE material?

Yes, our JEE Physics Laws Of Motion MCQs Set 27 include the latest type of questions, such as Assertion-Reasoning and Case-based MCQs. 50% of the JEE paper is now competency-based.

How do practicing Physics MCQs help in scoring full marks in JEE exams?

By solving our JEE Physics Laws Of Motion MCQs Set 27, JEE students can improve their accuracy and speed which is important as objective questions provide a chance to secure 100% marks in the Physics.

Do you provide answers and explanations for JEE Physics Laws Of Motion MCQs Set 27?

Yes, Physics MCQs for JEE have answer key and brief explanations to help students understand logic behind the correct option as its important for 2026 competency-focused JEE exams.

Can I practice these Physics JEE MCQs online?

Yes, you can also access online interactive tests for JEE Physics Laws Of Motion MCQs Set 27 on StudiesToday.com as they provide instant answers and score to help you track your progress in Physics.