Every key Kinematics formula, definition and theorem for JEE Main Physics in one place — with common examiner traps and worked examples. Free to read; blurt from memory, then check your gaps.
Syllabus — topics coveredNTA · 12 sub-topics
Frame of reference
Motion in a straight line
Speed and velocity
Uniform and non-uniform motion
Average speed and instantaneous velocity
Uniformly accelerated motion
Velocity-time and position-time graphs
Relations for uniformly accelerated motion
Relative velocity
Motion in a plane
Projectile motion
Uniform circular motion
Motion Basics: Distance, Velocity, Acceleration
Kinematics & frame of reference: Describing motion (position vs time) without its cause. A frame= origin + axes + clock; motion is absolute (fixed frame) or relative (moving frame).
Comparative: scalars vs vectors of motion
Quantity
Type
Sign?
Note
Distance / path
scalar
≥0
never decreases
Displacement Δr
vector
±
end-points only
Speed ∣v∣
scalar
≥0
instant: =∣v∣; avg speed ≥∣vav∣
Velocity v
vector
±
tangent to path
Distance vs displacement
▸Distance: total path covered (≥0). DisplacementΔr=r2−r1 (vector).
▸∣Δr∣≤ distance — equal only for straight-line motion with no reversal.
Average velocity / speed
vav=ΔtΔr;avg speed=Δtdistance
Δr= displacement, Δt= time interval; avg speed ≥∣vav∣; vav= chord slope on x-t
Instantaneous velocity / acceleration
v=dtdr;a=dtdv=dt2d2r
v= tangent slope on x-t; a= slope on v-t
🚫 Examiner Trap · Motion basics
(1) v=0 does NOT mean a=0 — at the top of a throw v=0, a=g. (2) Negative velocity means direction, not slowing down (slowing ⇔a opposes v). (3) avg velocity = avg speed in general; over a closed loop vav=0 but avg speed =0.
Motion types
▸Uniform: equal displacements in equal times ⇒v const, a=0.
▸Non-uniform: v changes; if a const → uniformly accelerated.
Variable acceleration (calculus)
Three forms of a
v=dtdx;a=dtdv;a=vdxdv
use a=vdv/dx when a is a function of position x
Method (choose by what a depends on)
▸a(t) given: v=u+∫adt, then x=x0+∫vdt.
▸a(x) given: ∫vdv=∫adx (separate variables — don't integrate in t).
▸a(v) given: ∫adv=∫dt or ∫avdv=∫dx.
⚡ Shortcut · Which calculus form?
Need v(x) but only have a? Use a=vdv/dx to skip time entirely. Need x(t)? Integrate twice in t. Picking the wrong form wastes the most exam time here.
Sn= distance covered during the nth second alone (a velocity-like quantity), NOT total distance in n s
🚫 Examiner Trap · Equations of motion
(1) Valid only while a is constant in magnitude AND direction — not for a(t). (2) Use displacement s in v2=u2+2as, not distance. (3) Sn is per-second distance, not total. (4) Fix + direction FIRST and keep u,v,a,s signed throughout.
Motion under gravity (a=g≈9.8m s−2)
Thrown up with speed u
tasc=gu=tdesc;Hmax=2gu2;T=g2u
tasc= rise time, Hmax= peak height, T= total flight time; returns with the same speed u
Free fall from rest
v=gt;h=21gt2;v=2gh
h= fall height, v= speed after falling h
Stopping distance
d=2au2∝u2
a= retardation; double the speed ⇒4× stopping distance
⚡ Shortcut · Galileo's odd-number rule
From rest, distances in successive equal time intervals are 1:3:5:7:… A body crosses any height twice with equal speed; t1,t2 are symmetric about the apex and t1t2=2h/g.
🚫 Examiner Trap · Gravity sign
Choose UP as +⇒a=−g throughout (rise and fall). The most common slip is flipping g's sign at the top — don't; only v reverses.
Motion Graphs
x-t (parabola if a=0) and v-t (area = displacement).Comparative: what slope & area mean
Graph
Slope gives
Area gives
x–t
velocity v
— (no meaning)
v–t
acceleration a
displacement (signed)
a–t
jerk da/dt
Δv (change in velocity)
Position–time (x-t)
▸Tangent slope = instantaneous velocity; chord slope = average velocity.
▸Straight ⇒ uniform velocity; parabola ⇒ uniform accn. Curving up ⇒a>0, down ⇒a<0.
(1) On v-t, area below the axis is negative displacement — for distance, add the magnitudes. (2) x-t slope is velocity, NOT acceleration. (3) No graph can be vertical (infinite velocity/accn). (4) A horizontal x-t tangent ⇒v=0 (turning point), but a may be =0.
⚡ Shortcut · Sign clues
v and (v-t slope) same sign ⇒ speeding up; opposite⇒ slowing. The particle reverses direction where the v-t curve crosses the time-axis.
Continuity
▸Position and velocity change continuously — never by a jump (a velocity jump needs an infinite force). So x-t is smooth (no corners) and v-t has no gaps.
▸Acceleration can jump (a force switched on/off): a-t may have steps, and v-t then has a corner there.
Vectors
Scalar vs vector: Scalar: magnitude only (distance, speed, mass). Vector: magnitude + direction (displacement, velocity, force); obeys triangle / parallelogram law.
Parallelogram law of addition.
Resultant (angle θ between A,B)
R=A2+B2+2ABcosθ
A,B= magnitudes; direction of R from A: tanα=A+BcosθBsinθ
(1) Add vectors head-to-tail, never add magnitudes (∣A+B∣=A+B unless parallel). (2) n^ (cross-product direction) by the right-hand rule — order matters. (3) Components use the angle WITH that axis: Acosθ along the axis θ is measured from.
⚡ Shortcut · Resolved motion
Plane motion = two independent 1-D motions along ⊥ axes; solve x and y separately. This is the entire basis of projectile motion.
Relative Velocity, River–Boat & Rain–Man
Relative velocity
vAB=vA−vB;vAB=−vBA
vAB= velocity of A as seen from B; vA,vB= ground velocities
Swimmer v (relative to water) + river u= ground velocity; drift =ud/v when heading straight across.Comparative: river crossing (d width, u river, v swim)
Goal
Heading
Result
Min time
straight across (θ=0)
t=vd, drift =vud
Zero drift
upstream, sinθ=vu
t=v2−u2d
General θ
θ to normal
t=vcosθd
If v<u (slow swimmer)
▸Cannot reach the point directly opposite. Least drift: head upstream at θ to the normal (the perpendicular to the bank) with sinθ=uv; driftmin=vdu2−v2.
Rain relative to man =vr−vm.
🎯 Exam · Rain–man
Hold the umbrella along vrm=vr−vm: tilt from vertical by θ=tan−1vrvmtowards your motion. vr= rain speed, vm= man's speed.
🚫 Examiner Trap · Relative velocity
(1) Order matters: vAB=vA−vB (the second subscript is the observer). (2) Min-time and min-drift headings are different — min time means head straight across (accept drift). (3) Tilt the umbrella INTO the relative-velocity direction, toward your motion, not away.
Same idea, other set-ups
▸Aeroplane in wind= boat in river (air is the river). To fly due N in an E-wind w at airspeed v: head W of N with sinθ=vw; ground speed v2−w2.
▸Ball in a lift accelerating up at a: relative to the lift use geff=g+a (down at a: g−a; free fall: 0).
▸Two projectiles in flight: relative acceleration =g−g=0, so each sees the other move in a straight line at constant velocity; they collide only if vrel points along the line joining them.
▸Closest approach (constant vrel, starting separation r0): dmin=∣vrel∣∣r0×vrel∣ at t=−∣vrel∣2r0⋅vrel.
T= time of flight, H= max height, R= horizontal range; also R=4H/tanθ
Key facts
▸R is maximum at θ=45∘: Rmax=u2/g. Same R for θ and 90∘−θ (complementary).
▸At the top vy=0, speed =ucosθ (NOT zero); T=2tasc.
Comparative: launch types
Launch
Flight time
Range
Ground, angle θ
g2usinθ
gu2sin2θ
Horizontal from h
g2h
ug2h
Up incline α
gcosα2usinθ
see below
Speed & direction at time t
v=u2−2usinθgt+g2t2;tanϕ=ucosθusinθ−gt
ϕ= angle of the velocity with the horizontal at time t
θ from the incline, α = incline angle, R along the incline.
Incline (launch θ to incline of angle α)
R=gcos2αu2[sin(2θ+α)−sinα];Rmax↑=g(1+sinα)u2
max range up the plane at θ=4π−2α; down the plane: Rmax=g(1−sinα)u2
🚫 Examiner Trap · Projectile motion
(1) At the top the speed is ucosθ, not zero — only vy=0. (2) g acts at every point, including the top. (3) Horizontal range needs sin2θ (so θ=45∘ max), not sinθ. (4) For horizontal projection, time depends only on height h, not on u.
Circular Motion (Kinematics)
Uniform circular motion: Motion on a circle of radius r at constant speed v. Speed is constant but v (direction) changes ⇒ the body is accelerated (centripetal).
v tangent; ac toward the centre.
Angular velocity & speed
ω=dtdθ;v=rω
ω= angular velocity (rad/s), r= radius; ω is the same for every point of a rigid body
Centripetal acceleration
ac=rv2=ω2r=4π2ν2r
directed radially inward (toward centre); ν= frequency
Period & frequency
T=ω2π=v2πr;ν=T1;v=2πrν
T= period (s), ν= frequency (Hz)
Comparative: centripetal vs tangential accn
Centripetal ac
Tangential at
Direction
radially inward
along tangent (∥v)
Formula
v2/r=ω2r
dv/dt=rα
Changes
direction of v
magnitude (speed)
Uniform CM
present
zero
Non-uniform: net acceleration
a=ac2+at2;tanϕ=acat
α= angular acceleration; ϕ= angle of net a from the radius
🚫 Examiner Trap · Circular motion
(1) Uniform circular motion IS accelerated — 'constant speed' fools students into writing a=0. (2) ac points INWARD, not outward (no real 'centrifugal' force in an inertial frame). (3) Here only kinematics: centripetal forcemv2/r, banking & vertical circles are dynamics — see Laws of Motion.
What are the most important Kinematics formulas for JEE Main?
This Kinematics formula sheet covers all the high-yield Physics formulas, definitions and theorems you need for JEE Main, across Frame of reference, Motion in a straight line, Speed and velocity, Uniform and non-uniform motion, Average speed and instantaneous velocity — each shown with the key result and, where useful, a worked example.
Is this Kinematics formula sheet free?
Yes — the full chapter formula sheet is free to read online, no login or payment required.
How should I revise Kinematics formulas?
Blurt the Kinematics formulas from memory, then check against this sheet to find your gaps — and practise a few previous-year questions on the chapter to make sure you can apply them under time pressure.