JEE Physics Laws Of Motion MCQs Set 28

Physics Objective Questions and Answers: Laws Of Motion

Access targeted multiple-choice questions for Laws Of Motion designed to align with the latest JEE academic syllabus for JEE Physics. These objective practice sets help students evaluate their conceptual understanding and improve exam readiness.

Download Laws Of Motion MCQs with Answers

View or download the dedicated Laws Of Motion MCQ resource below. Practicing these 50 objective questions regularly builds familiarity with standard exam patterns and helps secure higher marks in final Physics evaluations.

Multiple Choice Questions

Question 1:
Assertion (A): On a rainy day, it is difficult to drive a car or bus at high speed.
Reason (R): The value of the coefficient of friction is lowered due to wetting of the surface.
(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. Wet roads reduce μ, so the maximum friction available for braking and turning is less.
2. The Reason explains the Assertion.

Teacher's Note:
1. v_max² = μrg on a flat turn.

Question 2: A body of mass M hits normally a rigid wall with velocity V and bounces back with the same velocity. The impulse experienced by the body is
(a) MV
(b) 1.5 MV
(c) 2 MV
(d) zero
Show Answer & Explanation

Answer: (c) 2 MV

Explanation:
1. Change in momentum = MV − (−MV).
2. Impulse = 2MV.

Teacher's Note:
1. The velocity reverses, so the change doubles.

Question 3: A person sitting in an open car moving at constant velocity throws a ball vertically up into the air. The ball falls
(a) outside the car
(b) in the car ahead of the person
(c) in the car to the side of the person
(d) exactly in the hand which threw it up
Show Answer & Explanation

Answer: (d) exactly in the hand which threw it up

Explanation:
1. The ball keeps the car's horizontal velocity and the car does not accelerate.
2. So the ball stays above the hand and falls back into it.

Teacher's Note:
1. Horizontal velocities are equal, so there is no relative horizontal motion.

Question 4: If the rope of a lift breaks suddenly, the tension exerted by the surface of the lift (a = acceleration of the lift) is
(a) mg
(b) m(g + a)
(c) m(g − a)
(d) 0
Show Answer & Explanation

Answer: (d) 0

Explanation:
1. After the rope breaks, the lift and the body both fall freely with acceleration g.
2. The body feels weightlessness, so the contact force (tension) is zero.

Teacher's Note:
1. Free fall means zero apparent weight.

Question 5: A block of mass m₁ lies on a smooth horizontal table and is connected by a light string over a frictionless pulley at the table's edge to a hanging block of mass m₂. The acceleration of the system is
(a) \( a=\frac{m_2g}{m_1+m_2} \)
(b) \( a=\frac{m_1g}{m_1+m_2} \)
(c) \( a=\frac{m_1}{(m_1+m_2)g} \)
(d) \( a=\frac{m_2}{(m_1+m_2)g} \)
Show Answer & Explanation

Answer: (a) \( a=\frac{m_2g}{m_1+m_2} \)

Explanation:
1. The driving force is m₂g and the total mass moving is m₁ + m₂.
2. So a = m₂g/(m₁ + m₂).

Teacher's Note:
1. Treat both blocks as one system along the string.

Question 6: A particle of mass m moves with velocity v₁ and is given an impulse so that its velocity becomes v₂. The impulse is equal to
(a) \( m(\vec v_2-\vec v_1) \)
(b) \( m(\vec v_1-\vec v_2) \)
(c) \( m(\vec v_2+\vec v_1) \)
(d) \( 0.5\,m(\vec v_2-\vec v_1) \)
Show Answer & Explanation

Answer: (a) \( m(\vec v_2-\vec v_1) \)

Explanation:
1. Impulse = change in momentum = m v₂ − m v₁.
2. So it equals m(v₂ − v₁).

Teacher's Note:
1. Final minus initial momentum.

Question 7: If n bullets each of mass m are fired with a velocity v per second from a machine gun, the force required to hold the gun in position is
(a) \( (n+1)mv \)
(b) \( \frac{mv}{n} \)
(c) \( \frac{mv}{n^{2}} \)
(d) \( mnv \)
Show Answer & Explanation

Answer: (d) \( mnv \)

Explanation:
1. Momentum given to the bullets per second = n m v.
2. The force needed to keep the gun in place equals this rate of change, nmv.

Teacher's Note:
1. Force equals momentum ejected per second.

Question 8: What are the effects if a force acts on a moving body in a direction perpendicular to the direction of motion?
(a) The speed changes uniformly
(b) The acceleration changes uniformly
(c) The direction of motion changes
(d) All of these
Show Answer & Explanation

Answer: (c) The direction of motion changes

Explanation:
1. A perpendicular force does no work, so the speed stays constant.
2. It changes the direction of motion only.

Teacher's Note:
1. Perpendicular force gives centripetal acceleration.

Question 9: In an explosion, a body breaks into two pieces of unequal masses. In this
(a) both parts will have numerically equal momentum
(b) the lighter part will have more momentum
(c) the heavier part will have more momentum
(d) both parts will have equal kinetic energy
Show Answer & Explanation

Answer: (a) both parts will have numerically equal momentum

Explanation:
1. The body was initially at rest, so the total momentum is zero.
2. The two parts must have equal and opposite momenta, hence equal magnitudes.

Teacher's Note:
1. Momentum is conserved; energy is not shared equally.

Question 10: Match the columns.
Column IColumn II
(A) Inertia(1) \( 10^{5}\ \text{g cm s}^{-1} \)
(B) Recoil of a gun(2) kg f
(C) 1 kg m s\( ^{-1} \)(3) Newton's third law of motion
(D) Weight(4) Newton's first law of motion

(a) A-2, B-3, C-1, D-4
(b) A-1, B-3, C-4, D-2
(c) A-4, B-2, C-1, D-3
(d) A-4, B-3, C-1, D-2
Show Answer & Explanation

Answer: (d) A-4, B-3, C-1, D-2

Explanation:
1. Inertia is described by the first law.
2. Gun recoil is an action-reaction effect.
3. 1 kg m/s = 1000 g × 100 cm/s = 10⁵ g cm/s.
4. Weight can be expressed in kg f.

Teacher's Note:
1. Link each concept with its law or unit.

Question 11: The frictional force that opposes relative motion between surfaces in contact is called ...X... and denoted by ...Y.... X and Y are
(a) static friction, f_s
(b) kinetic friction, f_s
(c) kinetic friction, f_k
(d) static friction, f_k
Show Answer & Explanation

Answer: (c) kinetic friction, f_k

Explanation:
1. Friction during relative motion is kinetic friction.
2. It is denoted by f_k.

Teacher's Note:
1. Kinetic friction opposes sliding.

Question 12: Consider the following statements and select the incorrect statement(s). I. To move a football at rest, someone must kick it. II. To throw a stone upwards, one has to give it an upward push. III. A breeze causes the branches of a tree to become stationary. IV. A strong wind can move even heavy objects.
(a) Only I
(b) Only III
(c) III and IV
(d) I and II
Show Answer & Explanation

Answer: (b) Only III

Explanation:
1. Statements I, II and IV agree with the idea that a force is needed to change the state of motion.
2. A breeze moves the branches rather than making them stationary, so III is incorrect.

Teacher's Note:
1. Force changes motion; a breeze produces motion.

Question 13: A particle rests on the top of a hemisphere of radius R. The smallest horizontal velocity that must be imparted to the particle if it is to leave the hemisphere without sliding down is
(a) \( \sqrt{gR} \)
(b) \( \sqrt{2gR} \)
(c) \( \sqrt{3gR} \)
(d) \( \sqrt{5gR} \)
Show Answer & Explanation

Answer: (a) \( \sqrt{gR} \)

Explanation:
1. The particle leaves the surface at the top when mg = mv²/R.
2. So v = √(gR).

Teacher's Note:
1. The normal reaction becomes zero.

Question 14: Which motion does not require a force to maintain it?
(a) Uniform circular motion
(b) Elliptical motion
(c) Uniform straight line motion
(d) Projectile motion
Show Answer & Explanation

Answer: (c) Uniform straight line motion

Explanation:
1. Uniform motion along a straight line has zero acceleration, so no net force is needed.
2. Circular, elliptical and projectile motions all involve acceleration.

Teacher's Note:
1. Zero acceleration means zero net force.

Question 15: Which of the following statements are correct? I. Newton's first law of motion defines force. II. Newton's first law of motion defines inertia. III. Newton's first law of motion is a measure of force.
(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. The first law qualitatively defines force as the cause of change of the state of motion and defines inertia.
2. It is the second law, not the first, that measures force.

Teacher's Note:
1. Force is measured by the second law.

Question 16: Two blocks of masses 2 kg and 4 kg are attached by an inextensible light string, the 4 kg block above the 2 kg block, and a force of 120 N pulls the blocks vertically upward on the 4 kg block. The tension in the string connecting them is (g = 10 m/s²)
(a) 20 N
(b) 15 N
(c) 35 N
(d) 40 N
Show Answer & Explanation

Answer: (d) 40 N

Explanation:
1. Total weight = 60 N, so a = (120 − 60)/6 = 10 m/s².
2. For the 2 kg block, T − 20 = 2 × 10, so T = 40 N.

Teacher's Note:
1. Find the common acceleration, then apply F = ma on the lower block.

Question 17: The net force on a rain drop falling with a constant speed is
(a) the weight of the drop W
(b) the viscous drag of air F
(c) W + F + force of buoyancy
(d) zero
Show Answer & Explanation

Answer: (d) zero

Explanation:
1. Constant speed means zero acceleration.
2. The weight is balanced by the drag and buoyancy, so the net force is zero.

Teacher's Note:
1. Terminal velocity: balanced forces.

Question 18: Two bodies of masses 1 kg and 2 kg moving with the same velocities are stopped by the same force. The ratio of their stopping distances is
(a) 1 : 2
(b) 2 : 1
(c) \( \sqrt2:1 \)
(d) \( 1:\sqrt2 \)
Show Answer & Explanation

Answer: (a) 1 : 2

Explanation:
1. Work done = F s = ½ m v², so s ∝ m for the same F and v.
2. The ratio is 1 : 2.

Teacher's Note:
1. Stopping distance is proportional to mass here.

Question 19: A car takes a circular turn with uniform speed u. If the reaction at the inner and outer wheels are R₁ and R₂, then
(a) \( R_1=R_2 \)
(b) \( R_1 \lt R_2 \)
(c) \( R_1 \gt R_2 \)
(d) none of these
Show Answer & Explanation

Answer: (b) \( R_1 \lt R_2 \)

Explanation:
1. The car tends to topple outward, so the load shifts to the outer wheels.
2. The outer wheels have the greater reaction, R₂ > R₁.

Teacher's Note:
1. Torque balance about the centre of mass.

Question 20: Rocket engines lift a rocket from the earth's surface because hot gases with high velocity
(a) push against the air
(b) push against the earth
(c) react against the rocket and push it up
(d) heat up the air which lifts the rocket
Show Answer & Explanation

Answer: (c) react against the rocket and push it up

Explanation:
1. The rocket pushes the gases down and the gases push the rocket up (Newton's third law).
2. It works even in vacuum, so it needs neither the air nor the earth.

Teacher's Note:
1. Rocket propulsion is momentum conservation.

Question 21: When a body is stationary
(a) there is no force acting on it
(b) the force acting on it is not in contact with it
(c) the combination of forces acting on it balances each other
(d) the body is in vacuum
Show Answer & Explanation

Answer: (c) the combination of forces acting on it balances each other

Explanation:
1. A body at rest has zero acceleration, so the net force is zero.
2. Forces may still act on it, but they balance.

Teacher's Note:
1. Rest means a balanced set of forces, not no forces.

Question 22: On a railway curve the outside rail is laid higher than the inside one so that the resultant force exerted on the wheels of the rail car by the tops of the rails will
(a) have a horizontal inward component
(b) be vertical
(c) equilibriate the centripetal force
(d) be decreased
Show Answer & Explanation

Answer: (a) have a horizontal inward component

Explanation:
1. The normal reaction is tilted towards the centre because of the banking.
2. Its horizontal inward component supplies the centripetal force.

Teacher's Note:
1. Banking tilts the normal force inward.

Question 23:
Assertion (A): Friction is a necessary evil.
Reason (R): Though friction dissipates power, without friction we cannot walk.
(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. Friction wastes energy as heat but is needed to walk, drive and hold objects.
2. The Reason gives both sides of the idea and explains the Assertion.

Teacher's Note:
1. Friction has both good and bad effects.

Question 24: Choose the correct statement(s). I. Recoiling of a gun is an application of the principle of conservation of linear momentum. II. Explosion of a bomb is based on the second law of motion.
(a) I only
(b) II only
(c) I and II
(d) none of these
Show Answer & Explanation

Answer: (a) I only

Explanation:
1. Gun recoil follows from conservation of linear momentum, so I is correct.
2. An explosion is also explained by momentum conservation (internal forces), so II is not the right principle.

Teacher's Note:
1. Internal forces change the momentum of parts, not of the whole.

Question 25: A body whose momentum is constant must have constant
(a) velocity
(b) force
(c) acceleration
(d) all of the above
Show Answer & Explanation

Answer: (d) all of the above

Explanation:
1. Constant momentum means constant velocity for a fixed mass.
2. Then the acceleration is zero and the net force is zero (a constant).

Teacher's Note:
1. Constant p implies zero acceleration and force.

Free study material for Physics

Laws Of Motion Objective Questions & Solutions for JEE Physics

JEE Physics Laws Of Motion Objective Test Questions

Review structured objective questions for JEE Physics Laws Of Motion. Built according to official JEE guidelines, these MCQ sets support daily revision and core concept reinforcement.

NCERT-Aligned Objective Questions and Solutions

Cross-reference your completed choices with comprehensive NCERT solutions for JEE Physics to ensure absolute clarity across all sub-topics in this chapter.

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 28?

You can get most exhaustive JEE Physics Laws Of Motion MCQs Set 28 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 28 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 28, 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 28?

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 28 on StudiesToday.com as they provide instant answers and score to help you track your progress in Physics.