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SHM Teevra Series

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Periodic Motion

It is the motion Which Repeats itself


after Fixed Interval of Time .

Ex: Rotation of earth, Revolution of earth


Periodic Motion
Time Period
Oscillatory Motion
It is the To & Fro motion about a Mean Position

(a) Motion of pendulum (b) To & fro motion of ball


Oscillatory Motion
All oscillatory motions are periodic, but All
Periodic Motions are not Oscillatory

Periodic Motion

Oscillatory Motion
SHM
It is a special case of oscillatory motion in which
Acceleration is always Directed Towards Mean Position
& is proportional to Displacement from M.P.
E.P. M.P. E.P.
x = A sin (𝜔t)
SHM

-ve MP A +ve

t=0 v

time =t
Equation of SHM
t=0
T/4

T/2

T A/2

T1 T2

-ve MP +ve
JEE Main 25th Jan 2023 S-2

A particle executes simple harmonic motion


between x = -A and x = +A. If time taken by
particle to go from x = 0 to A/2 is 2 s; then time
taken by particle in going from x = A/2 to A is

A 3s

B 2s

C 4s

D 1.5s
JEE Main 25th Jan 2023 S-2

A particle executes simple harmonic motion


between x = -A and x = +A. If time taken by
particle to go from x = 0 to A/2 is 2 s; then time
taken by particle in going from x = A/2 to A is

A 3s

B 2s

C 4s

D 1.5s
Energy
T

U
X
JEE Main 13th April 2023 S-2

A particle executes SHM of amplitude A. The


distance from the mean position when it's
kinetic energy becomes equal to its potential
energy is :

A √2A

B 1/2 A

C 1/√2 A

D 2A
JEE Main 13th April 2023 S-2

A particle executes SHM of amplitude A. The


distance from the mean position when it's
kinetic energy becomes equal to its potential
energy is :

A √2A

B 1/2 A

C 1/√2 A

D 2A
Remember!!!
Kinetic Energy oscillates with
double the frequency of
oscillation.

● fEnergy= 2 fSHM
MP
t=0 t=0
t=0

t=0

x = A sin ( ωt + Φ0)
Φ0= Initial Phase
MP
t=0 t=0
t=0

t=0

x = A sin ( ωt + Φ0)
Φ0= Initial Phase
Shifted SHM

Origin MP
t=0
JEE Main 10th April 2023 S-1

A particle executes S.H.M. of amplitude A along


x-axis. At t = 0, the position of the particle is
x = A/2 and it moves along positives x-axis. The
displacement of particle in time t is
x = A sin(ωt + δ), then the value δ will be

A π/4

B π/2

C π/3

D π/6
JEE Main 10th April 2023 S-1

A particle executes S.H.M. of amplitude A along


x-axis. At t = 0, the position of the particle is
x = A/2 and it moves along positives x-axis. The
displacement of particle in time t is
x = A sin(ωt + δ), then the value δ will be

A π/4

B π/2

C π/3

D π/6
JEE Main 13th April 2023 S-1

Which graph represents the difference between


total energy and potential energy of a particle
executing SHM vs it's distance from mean
position?

A B

C D
JEE Main 13th April 2023 S-1

Which graph represents the difference between


total energy and potential energy of a particle
executing SHM vs it's distance from mean
position?

A B

C D
JEE Main 30th Jan 2023 S-2

The velocity of a particle executing SHM varies


with displacement (x) as 4v2 = 50 - x2 . The time
period of oscillations is x/7 s. The value of x
is_____.
JEE Main 30th Jan 2023 S-2

The velocity of a particle executing SHM varies


with displacement (x) as 4v2 = 50 - x2 . The time
period of oscillations is x/7 s. The value of x
is_____.

Ans : 88
A block of mass M is placed on a platform which is
tied to a spring (K) as shown. The complete block +
platform assembly oscillates simple harmonically in
vertical direction. Find max amplitude such that
block doesn't leave platform.

A 𝜔2/g
M

B g/𝜔2

C 𝜔/g

D g/𝜔
M
A block of mass M is placed on a platform which is
tied to a spring (K) as shown. The complete block +
platform assembly oscillates simple harmonically in
vertical direction. Find max amplitude such that
block doesn't leave platform.

A 𝜔2/g
M

B g/𝜔2

C 𝜔/g

D g/𝜔
SHM of bodies in Equilibrium
● There should exist a point where net force on
particle is zero. This is called as mean position.
● A particle may or may not perform SHM about this
mean position.
SHM of bodies in Equilibrium
● To check, displace the particle slightly from its
mean position by distance x.
● If a net extra restoring force come into picture to
bring the particle back to its mean position, then
it will definitely perform SHM

Fnet = - kx
M
M
Hence A constant force only shifts M.P.
It does not impact time period of SHM.
a a
k k

M
JEE Main 6th April 2023 S-1

A mass m is attached to two strings as shown in


figure. The spring constants of two springs are K1
and K2. For the frictionless surface, the time
period of oscillation of mass m is

D
JEE Main 6th April 2023 S-1

A mass m is attached to two strings as shown in


figure. The spring constants of two springs are K1
and K2. For the frictionless surface, the time
period of oscillation of mass m is

D
M
1. Pulley and spring should be massless.
2. The coefficient of tension on the block
should be 1.

ni - coefficient of tension in the spring of


spring constant ki
M
M
M
m1 m2
l
a

C
Angular SHM
● There should exist a point where net torque on
particle is zero. This is called as mean position.

● A particle may or may not perform SHM about


this mean position.
Angular SHM
● To check, displace the particle slightly from its
mean position by angle 𝜃 .
● If a net extra restoring torque come into picture to
bring the particle back to its mean position, then it
will definitely perform SHM.

𝜏net ∝ 𝜃
𝜏net = - k𝜃

where I = MOI about axis of Rotation


Simple Pendulum
Simple Pendulum

● It is Independent of mass of bob.


Second’s Pendulum

● Its length is 1 m.
● Its Time period is 2 seconds.
● Time period is independent of mass of bob
SIMPLE PENDULUM

a
a
L

→a
Physical Pendulum

Hinge

● ℓ = distance of COM from


hinge point. l

CM
M,L

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