NEET Physics – Motion in One Dimension
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| Motion in One Dimension explained with Mechanics, Kinematics, Dynamics, and Frame of Reference for NEET aspirants. |
Chapter 1: Basic Concepts of Mechanics (Complete Notes)
1. What is Physics?
Physics is the branch of science that studies matter, energy, motion, and forces.
Example:
Why does a ball fall?
Why does a bike move?
Why do planets revolve around the Sun?
All these are studied in Physics.
2. What is Mechanics?
Mechanics is the branch of Physics that studies the motion of objects and the forces causing that motion.
Simple Definition
Mechanics = Study of motion + causes of motion.
Mechanics is divided into two parts
Mechanics
/ \
Kinematics Dynamics
3. Kinematics
Definition
Kinematics is the branch of mechanics that studies motion without considering the force causing it.
It tells us
Where the object is
How fast it moves
How far it moves
How long it takes
But NOT why it moves.
Example
A car moves with speed 40 km/h.
Kinematics studies
✔ Speed
✔ Distance
✔ Time
✔ Displacement
It does NOT study engine force.
4. Dynamics
Definition
Dynamics studies motion along with the forces responsible for the motion.
It answers
Why does the object move?
Example
A football moves because a player kicks it.
Dynamics studies the force of the kick.
Difference Between Kinematics and Dynamics
| Kinematics | Dynamics |
|---|---|
| Studies motion only | Studies motion + force |
| Force is ignored | Force is considered |
| Easier chapter | Uses Newton's Laws |
| Example: Speed | Example: Force |
5. Frame of Reference
This is one of the most important concepts in NEET.
Definition
A Frame of Reference is a coordinate system attached to an observer from which measurements of position and time are made.
Simply,
It is the point from which an observer watches motion.
It contains
(1) Observer
Who is watching?
Example
You
Driver
Passenger
Teacher
(2) Space Coordinate
Where is the object?
Usually represented by
x-axis
y-axis
z-axis
(3) Time Coordinate
When is the object observed?
Measured using a clock.
Example
A train is moving.
Passenger says
"I am at rest."
A person standing on the platform says
"The train is moving."
Both are correct because their frames of reference are different.
Important Points
Motion depends on
✔ Observer
✔ Position
✔ Time
There is NO Absolute Motion
Motion is always relative.
There is nothing called
❌ Absolute Motion
❌ Absolute Rest
Everything depends upon the observer.
Example
You are sitting inside a moving bus.
With respect to
Seat → You are at rest.
Road → You are moving.
Both answers are correct.
6. Rest and Motion
Rest
An object is at rest if its position does not change with respect to the observer.
Example
Book lying on a table.
Motion
An object is in motion if its position changes with time with respect to an observer.
Example
Running car.
Flying bird.
Moving train.
Remember
Motion requires
✔ Observer
✔ Position
✔ Time
7. Point Object (Particle)
Very important for NEET.
Definition
A point object is an object whose size is very small compared to the distance travelled, so its dimensions can be ignored.
Example
Bike length = 2 m
Distance travelled = 500 km
Compared to 500 km,
2 m is negligible.
So bike is treated as a point object.
Another Example
Earth revolves around the Sun.
Earth diameter = 12,742 km
Distance from Sun = 150 million km
Compared to this huge distance,
Earth behaves like a point object.
When can an object be treated as a Point Object?
Ignore size when
Distance travelled ≫ Size of object
Example
| Object | Distance | Point Object? |
|---|---|---|
| Car travelling 200 km | Yes | ✔ |
| Cricket ball moving 40 m | Yes | ✔ |
| Pencil moving 2 cm | No | ✖ |
8. Position
Position tells where an object is located with respect to a chosen origin.
Example
If a boy stands 5 m to the right of the origin,
Position = +5 m
If he stands 3 m to the left,
Position = −3 m
9. Origin
Origin is the reference point from which distances are measured.
Usually represented by
O
Example
<------|------|------|------>
-2 -1 O +1 +2
10. Coordinate System
Used to locate objects.
One-dimensional (1D)
Only x-axis
Example
Train on straight track.
Two-dimensional (2D)
x-axis and y-axis
Example
Football ground.
Three-dimensional (3D)
x-axis
y-axis
z-axis
Example
Flying aeroplane.
Important NEET Concepts
Observer
Person who measures motion.
Coordinate
Shows position.
Time
Shows when motion occurs.
Motion depends on observer.
Always remember
Motion is Relative.
Frequently Asked NEET Facts
SI Unit of Distance
metre (m)
SI Unit of Time
second (s)
SI Unit of Speed
m/s
SI Unit of Force
Newton (N)
Previous Year NEET Concepts
Example 1
A passenger sitting inside a moving train is
A) Moving with respect to train
B) At rest with respect to train
C) Moving with respect to seat
D) None
Answer
✅ B
Example 2
A car moves from Delhi to Jaipur.
The car is treated as
A) Rigid body
B) Point object
C) Fluid
D) None
Answer
✅ B
Example 3
Motion is
A) Absolute
B) Relative
C) Constant
D) None
Answer
✅ B
Formula Sheet (This Topic)
There are no numerical formulas in this introductory topic. Focus on understanding the concepts.
One-Page Revision
Mechanics
Study of motion and the causes of motion.
Kinematics
Motion only.
No force.
Dynamics
Motion + force.
Frame of Reference
Observer + coordinate system + time.
Motion
Position changes with time relative to an observer.
Rest
Position does not change relative to an observer.
Point Object
Size is negligible compared to the distance travelled.
Key Rule
There is no absolute rest or absolute motion; all motion is relative to the observer.
These notes provide a strong conceptual foundation for Motion in One Dimension, a high-weightage topic in the NEET Physics syllabus.
Internal Links
- Units and Measurements Notes for NEET
- Vector and Scalar Quantities
- Motion in Two Dimensions
- Laws of Motion
- Work, Energy and Power
- System of Particles and Rotational Motion
- Gravitation Notes
- Oscillations and SHM
- Mechanical Properties of Solids
- Mechanical Properties of Fluids
- Thermal Physics Complete Notes
- Waves and Sound Notes
- Complete NEET Physics Formula Sheet
- NEET Physics PYQs Chapter-wise
- Motion in One Dimension MCQs with Answers
- Motion in One Dimension Numericals for NEET
- Motion in One Dimension Revision Notes
- Class 11 Physics Complete Notes
- NEET Physics Mock Tests
- NEET Physics Study Plan
🔥 NEET Physics – Motion in One Dimension
Part 1 : Ultra-Hard NEET Numericals
Instructions
- Total Questions : 25
- Difficulty : NEET Advanced
- Use SI Units.
- Take g = 10 m/s² whenever required.
- Do not use calculator unless instructed.
Q1.
A car starts from rest and moves with a constant acceleration of 4 m/s² for 15 s. Calculate- Final velocity
- Total displacement
- Average velocity
Q2.
A train moving at 20 m/s accelerates uniformly to 50 m/s in 15 s. Find- Acceleration
- Distance travelled
Q3.
A body travels- 40 m East
- 30 m West
- 20 m East
- Total distance
- Displacement
Q4.
A particle moves with velocity v = 5 + 2t where t is in seconds. Find- Velocity after 8 s
- Displacement in first 8 s
Q5.
A ball is thrown vertically upward with speed 40 m/s. Calculate- Maximum height
- Time to reach highest point
- Total time of flight
Q6.
A runner completes- First half distance at 10 m/s
- Second half distance at 15 m/s
Q7.
A particle covers- 100 m in North direction
- 100 m in East direction
- Distance
- Displacement
Q8.
A car moving at 25 m/s stops uniformly in 5 seconds. Calculate- Retardation
- Stopping distance
Q9.
Two cars move towards each other. Car A = 30 m/s Car B = 20 m/s Initially separated by 500 m. Find time to meet.Q10.
A particle travels- 2 hours at 40 km/h
- 3 hours at 60 km/h
- Total distance
- Average speed
Q11.
A body starts from rest with acceleration 3 m/s² Find displacement in 12 seconds.Q12.
A train moving at 72 km/h crosses a 300 m platform in 30 s. Find length of train.Q13.
A cyclist increases speed uniformly from 5 m/s to 15 m/s over a distance of 100 m. Find acceleration.Q14.
A body moves 10 m East 10 m North 10 m West Find displacement.Q15.
A particle has velocity v = 20 − 5t Find- Time when particle stops
- Distance travelled till then
Q16.
A stone falls freely from a tower. It reaches ground in 6 s. Find- Height of tower
- Velocity on reaching ground
Q17.
A bus travels 80 km at 40 km/h and 120 km at 60 km/h. Find average speed.Q18.
A particle moves according to s = 4t² + 3t Find velocity after 5 seconds.Q19.
Two trains Length = 200 m each Speed = 15 m/s and 25 m/s move in opposite directions. Find time taken to cross each other.Q20.
A particle covers first one-third distance with speed 10 m/s remaining distance with speed 20 m/s Find average speed.Q21.
A body starts with velocity 15 m/s Acceleration 2 m/s² Find distance covered in 20 s.Q22.
A particle moves 50 m East 120 m West 70 m East Calculate displacement.Q23.
A train moving at 54 km/h crosses a man standing on platform in 12 seconds. Length of train?Q24.
A particle starts from rest. Acceleration = 5 m/s² Find distance travelled during 4th second.Q25. ⭐ NEET Challenge
A particle moves according to x = 5 + 4t + 2t² Find- Position after 6 s
- Velocity after 6 s
- Acceleration
- Distance covered between 2 s and 6 s
- Attempt all questions without looking at formulas.
- Write complete steps.
- Time yourself (45 minutes).
- Target Score : 25/25
🔥 Supplementary Part 2
Ultra-Hard Motion in One Dimension Numericals (Q26–Q50)
Instructions
- Difficulty: NEET Advanced
- Attempt without calculator.
- Take g = 10 m/s² unless otherwise stated.
Q26
A car accelerates uniformly from 10 m/s to 40 m/s in 12 seconds. Find:- Acceleration
- Distance travelled
Q27
A particle moves with velocity v = 8 + 3t. Find displacement during first 10 seconds.Q28
A train moving at 90 km/h crosses a pole in 18 s. Find length of train.Q29
A ball is projected vertically upward with speed 50 m/s. Find:- Maximum height
- Total time of flight
Q30
A body covers:- 120 m at 6 m/s
- 180 m at 9 m/s
Q31
Two cars move in the same direction. Car A = 18 m/s Car B = 24 m/s Initial gap = 240 m. Find time taken by B to overtake A.Q32
A particle starts from rest with acceleration 4 m/s². Find distance travelled during the 8th second.Q33
A cyclist slows uniformly from 12 m/s to rest in 6 s. Find stopping distance.Q34
A particle moves:- 40 m North
- 30 m East
- 40 m South
Q35
Velocity equation: v = 24 − 4t Find:- Time to stop
- Distance travelled
Q36
A freely falling stone reaches the ground with velocity 60 m/s. Find height of the tower.Q37
A train of length 180 m crosses a bridge of length 420 m in 24 s. Find speed of train.Q38
A body moves according to x = 3t² + 2t + 5. Find velocity at t = 8 s.Q39
A car travels:- 100 km at 50 km/h
- 150 km at 75 km/h
Q40
Two trains of lengths 250 m and 150 m move in opposite directions at 18 m/s and 22 m/s. Find crossing time.Q41
A particle starts from rest. Acceleration = 6 m/s². Find displacement after 15 seconds.Q42
A ball is thrown downward from a building with velocity 15 m/s. It reaches ground in 5 s. Find height of building.Q43
A particle covers one-fourth distance at 12 m/s and remaining distance at 24 m/s. Find average speed.Q44
Position equation: s = 2t³ − 5t² + 8. Find velocity at t = 3 s.Q45
A train moving at 54 km/h overtakes another moving at 36 km/h. Both trains are 150 m long. Find overtaking time.Q46
A body starts with velocity 20 m/s and acceleration 3 m/s². Find velocity after travelling 150 m.Q47
A particle moves:- 100 m East
- 60 m West
- 20 m East
- 40 m West
- Total distance
- Displacement
Q48
A stone is thrown upward from a cliff of height 80 m with speed 30 m/s. Find time taken to hit the ground.Q49
A particle has acceleration a = 4 m/s². Initial velocity = 6 m/s. Find displacement in first 12 s.Q50 ⭐ NEET Challenge
Position equation: x = 10 + 6t + 3t² Find:- Position at t = 8 s
- Velocity at t = 8 s
- Acceleration
- Distance travelled between 4 s and 8 s
Self Evaluation
| Score | Performance |
|---|---|
| 23–25 | Excellent (NEET Top Rank Level) |
| 18–22 | Very Good |
| 12–17 | Good, Needs Practice |
| Below 12 | Revise Theory & Formulae |
🔥 NEET Physics Mock Test
Motion in One Dimension (Part 3)
Time : 45 Minutes
Marks : 180
Correct : +4
Wrong : −1
Section A (MCQs)
A) m/s
B) m
C) km
D) s
A) Vector
B) Scalar
C) Tensor
D) None
A) Highest point
B) Lowest point
C) Throughout
D) Never
A) Circular path
B) Straight line without changing direction
C) Closed path
D) Random motion
A) Speed
B) Time
C) Displacement
D) Velocity
A) 1 m/s
B) 10 m/s
C) 0 m/s
D) −1 m/s
A) Constant speed only
B) Constant velocity
C) Variable speed
D) Variable direction
A) m
B) m/s
C) m/s²
D) km/h
A) Straight line
B) Circle
C) Parabola
D) Hyperbola
A) Speed
B) Distance
C) Velocity
D) Time
A)40 m B)20 m C)0 D)10 m
A)Total Distance/Total Time B)Displacement/Time C)v²-u² D)None
A)Rectilinear B)Circular C)Rotational D)Projectile
A)Positive acceleration B)Negative acceleration C)Zero acceleration D)Infinite acceleration
A)Velocity B)Distance C)Instantaneous Speed D)Average Speed
A)Speed B)Distance C)Acceleration D)Velocity
A)Absolute B)Relative C)Constant D)Uniform
A)g B)0 C)2g D)Depends on mass
A)m B)m/s C)m/s² D)km
A)Variable acceleration B)Constant acceleration C)Circular motion D)Random motion
A)Velocity B)Displacement C)Speed D)Acceleration
A)Acceleration B)Distance/Displacement C)Speed D)Force
A)Acceleration B)Velocity C)Force D)Momentum
A)Displacement B)Acceleration C)Time D)Distance
A)Zero acceleration B)Maximum acceleration C)Infinite acceleration D)Variable acceleration
A)Horizontal line B)Vertical line C)Curve D)Circle
A)Hour B)Second C)Minute D)Day
A)Velocity B)Acceleration C)Distance D)Displacement
A)s B)t C)u D)v
A)u B)a C)v D)s
Section B (Assertion-Reason)
Reason: There is no absolute rest.
Reason: Speed is scalar.
Reason: Distance is scalar.
Reason: Direction may change.
Section C (Numericals)
OMR Answer Sheet
| Q | Ans | Q | Ans | Q | Ans |
|---|---|---|---|---|---|
| 1 | ___ | 16 | ___ | 31 | ___ |
| 2 | ___ | 17 | ___ | 32 | ___ |
| 3 | ___ | 18 | ___ | 33 | ___ |
| 4 | ___ | 19 | ___ | 34 | ___ |
| 5 | ___ | 20 | ___ | 35 | ___ |
| 6 | ___ | 21 | ___ | 36 | ___ |
| 7 | ___ | 22 | ___ | 37 | ___ |
| 8 | ___ | 23 | ___ | 38 | ___ |
| 9 | ___ | 24 | ___ | 39 | ___ |
| 10 | ___ | 25 | ___ | 40 | ___ |
| 11 | ___ | 26 | ___ | 41 | ___ |
| 12 | ___ | 27 | ___ | 42 | ___ |
| 13 | ___ | 28 | ___ | 43 | ___ |
| 14 | ___ | 29 | ___ | 44 | ___ |
| 15 | ___ | 30 | ___ | 45 | ___ |
🔥 NEET Physics
Part 4 – Answer Key & Step-by-Step Solutions
Section A (MCQs)
| Q | Answer | Q | Answer | Q | Answer |
|---|---|---|---|---|---|
| 1 | B | 11 | C | 21 | C |
| 2 | B | 12 | A | 22 | B |
| 3 | A | 13 | A | 23 | B |
| 4 | B | 14 | B | 24 | B |
| 5 | C | 15 | C | 25 | A |
| 6 | C | 16 | B | 26 | A |
| 7 | B | 17 | B | 27 | B |
| 8 | C | 18 | A | 28 | C |
| 9 | A | 19 | B | 29 | C |
| 10 | C | 20 | B | 30 | C |
Section B (Assertion–Reason)
| Question | Correct Option |
|---|---|
| 31 | A (Both true, Reason correctly explains) |
| 32 | D (Assertion false, Reason true) |
| 33 | B (Both true, Reason not correct explanation) |
| 34 | D (Assertion false, Reason true) |
| 35 | A (Both true, Reason correctly explains) |
Section C (Numericals)
Given u = 0 m/s a = 5 m/s² t = 8 s
v = u + at
v = 0 + 5 × 8
Answer = 40 m/s
Distance = Speed × Time
= 20 × 30
Answer = 600 m
East = +60 West = -80
Displacement = 60 - 80 = -20 m
Answer = 20 m West
s = 45 m u = 0 g =10
45 = 5t²
t² =9
t =3 s
Answer = 3 s
Average Speed =120/2
Answer =60 km/h
s = ut + ½at²
=10×5 + ½×2×25
=50+25
Answer =75 m
a=(30−10)/4
=20/4
Answer =5 m/s²
Speed =180/12
Answer =15 m/s
Maximum Height H=u²/2g
=20²/(20)
=20 m
Answer =20 m
v=6+2t
=6+16
Answer =22 m/s
Score Analysis
| Marks | Performance |
|---|---|
| 170–180 | Outstanding ⭐⭐⭐⭐⭐ |
| 150–169 | Excellent |
| 120–149 | Very Good |
| 90–119 | Good |
| Below 90 | Needs Revision |
- Confusing distance with displacement.
- Using average velocity instead of average speed.
- Incorrect sign convention (+ and -).
- Using wrong kinematic equation.
- Mixing km/h and m/s units.
- Ignoring direction in vector quantities.
- Calculation mistakes in free-fall problems.
🔥 Part 5
Previous Year Question Bank (NEET / AIPMT / AIIMS Style)
This section contains NEET-style questions inspired by previous exam patterns. They are designed for practice and concept building.
A) 20 m B) 10 m C) 0 m D) 5 m
A) Velocity B) Acceleration C) Distance D) Displacement
A) m B) m/s C) m/s² D) km/h
🔥 PYQ Practice Set (Without Answers)
- A body covers 240 m in 30 s. Find average speed.
- A car accelerates from 10 m/s to 30 m/s in 5 s. Find acceleration.
- Define displacement with one example.
- Differentiate between speed and velocity.
- A particle moves according to x = 4 + 5t + 2t². Find velocity at t = 6 s.
- A train of length 250 m crosses a bridge of length 350 m in 24 s. Find speed.
- A freely falling body reaches the ground in 8 s. Find height.
- State any two differences between distance and displacement.
- Find stopping distance of a car moving at 30 m/s if retardation is 5 m/s².
- Find average speed if equal distances are covered at 20 km/h and 30 km/h.
🔥 Formula Revision Sheet
- v = u + at
- s = ut + ½at²
- v² = u² + 2as
- Average Speed = Total Distance / Total Time
- Average Velocity = Total Displacement / Total Time
- Distance = Speed × Time
- Acceleration = (v − u) / t
🎯 NEET Rapid Revision
- Motion is relative.
- Distance is scalar.
- Displacement is vector.
- Speed is scalar.
- Velocity is vector.
- Acceleration can be positive or negative.
- Retardation = Negative acceleration.
- Slope of displacement–time graph = Velocity.
- Slope of velocity–time graph = Acceleration.
- Area under velocity–time graph = Displacement.
