NEET Physics — Kinematics Complete Chapter Guide

Chapter Overview & Weightage

Kinematics is your first real physics chapter, and NEET rewards it generously. We typically see 2-3 questions every year, and most of them fall in the easy-to-medium bracket. If you nail the basics, these are free marks.

🎯 Exam Insider

Kinematics carries 4-5% weightage in NEET. Expect 2-3 questions — most frequently from projectile motion and equations of motion with graphical interpretation.

Year	NEET Q Count	Key Topics Tested
2025	3	Projectile motion, velocity-time graphs
2024	2	Relative motion, equations of motion
2023	3	Projectile on incline, motion under gravity
2022	2	Graph-based problems, river-boat
2021	2	Free fall, projectile range

The pattern is clear: projectile motion appears almost every year, and graphical interpretation of motion is a NEET favourite.

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Key Concepts You Must Know

Prioritised by exam frequency:

Tier 1 (Always asked)

Three equations of motion and when to use each
Projectile motion — time of flight, maximum height, range
Velocity-time and displacement-time graph interpretation
Motion under gravity (free fall, upward throw)

Tier 2 (Frequently asked)

Relative motion in 1D and 2D
River crossing problems (minimum time vs shortest path)
Projectile on an inclined plane
Displacement vs distance distinction

Tier 3 (Occasional)

Motion with variable acceleration (calculus-based)
Relative velocity of approach and separation

Important Formulas

Three Equations of Motion

For constant acceleration $a$ , initial velocity $u$ , final velocity $v$ , displacement $s$ , and time $t$ :

$v = u + at$

$s = ut + \frac{1}{2}at^2$

$v^2 = u^2 + 2as$

Use the first when time is given/needed. Use the third when time is NOT given and not needed. The second covers everything else.

Projectile Motion (Oblique)

For launch angle $\theta$ and initial speed $u$ :

Time of flight: $T = \dfrac{2u\sin\theta}{g}$

Maximum height: $H = \dfrac{u^2\sin^2\theta}{2g}$

Range: $R = \dfrac{u^2\sin 2\theta}{g}$

Maximum range occurs at $\theta = 45°$ and equals $R_{max} = \dfrac{u^2}{g}$ .

Relative Motion

$\vec{v}_{A/B} = \vec{v}_A - \vec{v}_B$

For river crossing:

Minimum time: Swim perpendicular to the river. Time $= \dfrac{d}{v_{swimmer}}$
Shortest path: Swim at an angle such that the resultant is perpendicular to the bank.

💡 Expert Tip

For projectile problems, always resolve the motion into horizontal (constant velocity) and vertical (constant acceleration $g$ ). Never mix the two components — that is the single most powerful trick in kinematics.

Solved Previous Year Questions

PYQ 1 — NEET 2024

Problem: A ball is thrown vertically upward with velocity $u$ . The displacement of the ball in the last 1 second before reaching the highest point is (take $g = 10$ m/s $^2$ ):

Solution:

At the highest point, $v = 0$ . We need displacement in the last 1 second.

Using $v = u' + at$ where $u'$ is velocity 1 second before the top:

$0 = u' - g(1) \implies u' = 10 \text{ m/s}$

Displacement in that last second:

$s = u't - \frac{1}{2}gt^2 = 10(1) - \frac{1}{2}(10)(1)^2 = 10 - 5 = \mathbf{5 \text{ m}}$

💡 Expert Tip

This result is universal — the displacement in the last second before the highest point is always $g/2 = 5$ m (for $g = 10$ m/s $^2$ ), regardless of the initial velocity. Memorise this shortcut.

PYQ 2 — NEET 2023

Problem: A projectile is fired at $60°$ above the horizontal with speed $20$ m/s. Find the speed at the highest point. (Take $g = 10$ m/s $^2$ )

Solution:

At the highest point, vertical velocity becomes zero. Only horizontal velocity survives:

$v_{top} = u\cos\theta = 20\cos 60° = 20 \times 0.5 = \mathbf{10 \text{ m/s}}$

⚠️ Common Mistake

Students often write the speed as zero at the highest point. That is the vertical component only. The horizontal component $u\cos\theta$ remains constant throughout the flight (no air resistance). The speed at the top is never zero (unless $\theta = 90°$ ).

PYQ 3 — NEET 2022

Problem: The velocity-time graph of a body is a straight line from $(0, 2)$ to $(4, 10)$ in SI units. Find the total displacement.

Solution:

This is a straight line on a v-t graph, so displacement = area under the curve (a trapezium):

$s = \frac{1}{2}(v_1 + v_2) \times t = \frac{1}{2}(2 + 10) \times 4 = \frac{1}{2}(12)(4) = \mathbf{24 \text{ m}}$

Difficulty Distribution

Difficulty	% of Questions	What to Expect
Easy	40%	Direct formula substitution, basic graph reading
Medium	45%	Projectile motion, relative motion
Hard	15%	Variable acceleration, projectile on incline

🎯 Exam Insider

NEET kinematics is more formula-friendly than JEE. About 40% questions can be solved by direct substitution into the equations of motion or projectile formulas. The remaining need a clear diagram and component resolution.

Expert Strategy

Week 1: Master the three equations of motion. You should be able to pick the right equation within 5 seconds of reading a problem. Solve 30 problems — 10 each on free fall, upward throw, and horizontal motion.

Week 2: Projectile motion deserves full focus. Practise both horizontal and oblique projection. Pay special attention to "find the angle for given conditions" type questions — these need you to work backwards from the range or height formula.

Week 3: Graph-based problems. NEET loves giving you a v-t or s-t graph and asking for acceleration, displacement, or velocity. The key skill: area under v-t graph = displacement, slope of s-t graph = velocity, slope of v-t graph = acceleration.

💡 Expert Tip

Toppers always draw a diagram with coordinate axes before solving projectile problems. Label the initial velocity components $u_x$ and $u_y$ , mark the acceleration direction ( $-g$ vertically), and the problem practically solves itself.

PYQ strategy: Last 5 years of NEET have about 12-14 kinematics questions. Group them by type: free fall, projectile, graphs, relative motion. You will notice that projectile problems repeat almost identical structures.

Common Traps

⚠️ Common Mistake

Trap 1 — Sign errors in vertical motion. When a ball is thrown upward, if you take upward as positive, then $a = -g$ . Students who forget the negative sign get the wrong time of flight. Always define your positive direction first and stick to it.

⚠️ Common Mistake

Trap 2 — Confusing displacement with distance. A ball thrown up and caught back has displacement = 0 but distance = $2H$ . NEET specifically tests this distinction. Read the question carefully — "displacement" and "distance" give different answers.

⚠️ Common Mistake

Trap 3 — Using wrong component in projectile range. The range formula $R = u^2\sin 2\theta / g$ works only when launch and landing are at the same height. For a projectile launched from a cliff or landing on a different level, you must use component equations separately.

⚠️ Common Mistake

Trap 4 — Complementary angles giving same range. $\theta$ and $(90° - \theta)$ give the same range but different heights and times. NEET may ask "which angle gives greater height for the same range" — the answer is always the larger angle.

⚠️ Common Mistake

Trap 5 — Relative velocity direction errors. In river-boat problems, students add velocities instead of doing vector subtraction. Draw the velocity triangle — river velocity is horizontal, swimmer velocity is at an angle — and use Pythagoras or trigonometry.