Motion in a Straight Line — Class 11 MCQs with Answers
Class 11 CBSE Physics · Chapter 3
66 practice questions · 22 Easy · 22 Medium · 22 Hard · Updated
Practise the most important Class 11 CBSE Physics questions from Chapter 3, "Motion in a Straight Line". You get 6 timed quizzes made from 66 NCERT-based MCQs, with answers and explanations. The questions are split into 22 Easy, 22 Medium and 22 Hard. Warm up on the basics, then move on to the exam-level questions that set top scorers in CBSE & Maharashtra HSC Board exams, JEE Main, MHT-CET, JEE Advanced and NEET UG apart.
To score well in "Motion in a Straight Line", focus on numericals, derivations and applying concepts. Each MCQ here is timed and uses exam-style marking (+4 correct, −1 wrong, 0 skipped). This trains you to stay accurate under time pressure, as real papers need. Every question has a short explanation, so a wrong answer becomes a quick lesson. It is the fastest way to fix gaps before a test.
Use this chapter for focused revision. Start with the Easy set to check your basics on Motion in a Straight Line, then move to Medium and Hard to practise applying them. Your accuracy, streaks and XP save automatically. This chapter also adds to your overall Class 11 Physics mastery score. 13 sample questions are solved in full below, with the answer and a worked explanation. Sign in free to start practising.
Key concepts: Motion in a Straight Line (Class 11 Physics)
One-dimensional kinematics: the difference between distance and displacement, speed and velocity, how position-time and velocity-time graphs encode motion, the three equations of uniformly accelerated motion, free fall under gravity, and relative velocity along a line.
- Distance versus displacement
- Distance is the total path length, a scalar that never decreases. Displacement is the straight-line change in position, a vector that can be zero even after a long journey.
- Average speed versus average velocity
- Average speed uses path length, so it can never be less than the magnitude of average velocity. The two differ whenever the motion reverses direction.
- Instantaneous velocity
- The limit of average velocity as the time interval shrinks to zero — mathematically dx/dt, and graphically the slope of the tangent to the position-time curve.
- Acceleration
- The rate of change of velocity. A negative acceleration does not mean slowing down; a body slows only when its velocity and acceleration point in opposite directions.
Motion in a Straight Line — important questions & MCQs with answers (Class 11 Physics)
13 solved questions from this chapter's difficulty levels, each with its answer and explanation. The other 53 are timed and scored when you sign in.
- Q1Easy
Velocity is:
A.ScalarB.Mass × timeC.Same as speedD.Vector (rate of change of position)✓ CorrectAnswer: D. Vector (rate of change of position)
Explanation: Velocity is a vector: it has both magnitude and direction, e.g. 5 m/s due north, unlike speed (5 m/s alone). Calling it 'same as speed' drops the direction — that is the trap.
- Q2Easy
SI unit of acceleration:
A.m/sB.m/s²✓ CorrectC.mD.kg·m/s²Answer: B. m/s²
Explanation: Acceleration a = Δv/Δt, so its unit is (m/s)/s = m/s², e.g. gaining 10 m/s every second is 10 m/s². Confusing it with velocity's unit m/s is the common slip.
- Q3Easy
v = u + at applies when:
A.AlwaysB.a variesC.u = 0D.a is constant✓ CorrectAnswer: D. a is constant
Explanation: v = u + at holds only for constant acceleration, e.g. a = 3 m/s² throughout a trip. If a varies with time this straight-line formula breaks down and calculus (v = u + ∫a dt) is needed instead.
- Q4Easy
Free fall is motion under:
A.Variable forceB.FrictionC.No forceD.Gravity alone✓ CorrectAnswer: D. Gravity alone
Explanation: Free fall is motion under gravity alone, with no air resistance or other force, e.g. a stone dropped falls at g ≈ 9.8 m/s². 'No force' is wrong since gravity itself is still acting on it.
- Q5Easy
Slope of v−t graph gives:
A.DisplacementB.VelocityC.Acceleration✓ CorrectD.PositionAnswer: C. Acceleration
Explanation: Slope of a velocity-time graph is a = dv/dt, giving acceleration, e.g. velocity rising 8 m/s over 4 s means slope = 2 m/s². Confusing this with the x-t graph's slope (velocity) is the common mix-up.
- Q6Medium
Car accelerates from rest to 20 m/s in 4 s. Acceleration:
A.20 m/s²B.4 m/s²C.16 m/s²D.5 m/s²✓ CorrectAnswer: D. 5 m/s²
Explanation: Acceleration a = Δv/Δt = (20 − 0)/4 = 5 m/s². Dividing the wrong way, 4/20, or forgetting to subtract the initial 0 m/s, produces the other listed distractors.
- Q7Medium
Body starts from rest, a = 4 m/s². Velocity after 5 s:
A.20 m/s✓ CorrectB.4 m/sC.5 m/sD.9 m/sAnswer: A. 20 m/s
Explanation: First equation of motion: v = u + at. With u = 0, a = 4 m/s², t = 5 s, v = 0 + 4×5 = 20 m/s. Don't forget to add u once it is nonzero in other problems.
- Q8Medium
Object falls 5 m in 1st second. Distance in 2nd second (g = 10):
A.10 mB.5 mC.15 m✓ CorrectD.20 mAnswer: C. 15 m
Explanation: With g = 10 m/s², total fall by t = 2 s is ½×10×4 = 20 m, and by t = 1 s it is ½×10×1 = 5 m, matching the given 1st-second value. Distance in the 2nd second = 20 − 5 = 15 m, not simply double the 5 m.
- Q9Medium
Body's x-t graph is a straight line (non-horizontal). Body has:
A.Constant velocity✓ CorrectB.Constant accelerationC.Variable velocityD.No motionAnswer: A. Constant velocity
Explanation: A straight, non-horizontal x-t line has constant slope, and since slope = dx/dt = velocity, that means constant velocity, e.g. rising 4 m every 2 s gives a steady 2 m/s. A curved x-t graph signals acceleration, not a straight one.
- Q10Medium
Velocity of A w.r.t. B = ?
A.v_A − v_B✓ CorrectB.v_A + v_BC.|v_A|·|v_B|D.v_A/v_BAnswer: A. v_A − v_B
Explanation: Relative velocity of A with respect to B is the vector difference v_AB = v_A − v_B, e.g. 20 m/s − 5 m/s = 15 m/s if both move the same way. Adding instead of subtracting only applies when they move oppositely.
- Q11Hard
Slope of position-time graph gives:
A.MassB.AccelerationC.ForceD.Velocity✓ CorrectAnswer: D. Velocity
Explanation: Instantaneous velocity is v = dx/dt, so the slope of a position-time graph directly gives velocity, e.g. a slope of 3 m/s means 3 m displacement each second — acceleration instead needs a v-t graph's slope.
- Q12Hard
Body decelerates from 20 m/s to rest in 4 s. Magnitude of acceleration:
A.20 m/s²B.4 m/s²C.5 m/s²✓ CorrectD.80 m/s²Answer: C. 5 m/s²
Explanation: Deceleration magnitude |a| = |v − u|/t = |0 − 20|/4 = 5 m/s². Dividing 20 by 4 correctly gives 5, not 4 — don't confuse the given time with the answer.
- Q13Hard
Object thrown vertically up with velocity u. Returns in time T. Then u =
A.2gTB.gTC.T/gD.gT/2✓ CorrectAnswer: D. gT/2
Explanation: By symmetry, time up equals time down, so the ball reaches its peak, where v = 0, at T/2. Then 0 = u − g(T/2) gives u = gT/2 — using the full time T instead of T/2 is the error behind u = gT.
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Start this chapter free →Motion in a Straight Line — FAQs
What are the key concepts in Class 11 Physics Motion in a Straight Line?+
One-dimensional kinematics: the difference between distance and displacement, speed and velocity, how position-time and velocity-time graphs encode motion, the three equations of uniformly accelerated motion, free fall under gravity, and relative velocity along a line. Key ideas include Distance versus displacement, Average speed versus average velocity, Instantaneous velocity, Acceleration.
What does Class 11 Physics Chapter 3 (Motion in a Straight Line) cover on XamBaaz?+
It has 66 NCERT-based MCQs on "Motion in a Straight Line": 22 Easy, 22 Medium and 22 Hard. Together they make 6 timed quizzes, and you never get the same set twice. Every question has an instant explanation. They help you prepare for CBSE & Maharashtra HSC Board exams, JEE Main, MHT-CET, JEE Advanced and NEET UG.
Are these "Motion in a Straight Line" questions free to practise?+
Yes. Sign in with Google to practise "Motion in a Straight Line" free. Full unlimited access is ₹999/year on a launch offer until 1 December 2026. No chapter is charged separately.
How should I revise "Motion in a Straight Line" for the exam?+
Start with the Easy quiz to check your basics, then try Medium and Hard to practise applying them. There are 6 timed quizzes on this chapter, so you can come back for a fresh set instead of one you have seen. Read each explanation, retry the questions you miss, and track your accuracy until it stays high.
Are these "Motion in a Straight Line" MCQs available with answers?+
Yes. 13 sample questions are shown here in full, each with the correct option and a step-by-step "Why" explanation. Sign in free with Google to start practising, with instant scoring.
Is there negative marking in the "Motion in a Straight Line" quizzes?+
Yes. The timed quizzes use exam-style marking: +4 for a right answer, −1 for a wrong one and 0 for a skip, the same negative marking as JEE Main, JEE Advanced and NEET UG. MHT-CET and CBSE board papers have no negative marking. Our mocks for those are scored their way.
What are the important questions from Motion in a Straight Line (Class 11 Physics)?+
The questions that matter most test Distance versus displacement, Average speed versus average velocity, Instantaneous velocity, Acceleration. This page shows 13 solved important MCQs with answers and explanations; all 66 questions on the chapter are available as timed quizzes once you sign in.
Is there an online quiz for Motion in a Straight Line?+
Yes — Class 11 Physics Motion in a Straight Line has timed online quizzes at Easy, Medium and Hard levels, with instant scoring and a worked explanation on every question. The first quiz on the chapter is free.