A particle oscillates along the x-axis according to the law, x(t) = x₀ ²((t)/(2)) where x₀ = 1 m . The kinetic energy (K) of the particle as a function of x is correctly represented by the graph.

Solution & Explanation

Related Formula
x(t) = x₀ ²((t)/(2)) = x₀ ((1 - t)/(2))
Core Logic

Given x₀ = 1 m, the position simplifies to:

x = (1 - t)/(2) 2x - 1 = - t t = 1 - 2x

Differentiating x(t) to find velocity v:

v = (dx)/(dt) = (1)/(2) t

Kinetic energy K is proportional to v²:

K = (1)/(2)mv² = (1)/(2)m ((1)/(4) ² t) = (m)/(8)(1 - ² t)

Substituting t = 1 - 2x:

K = (m)/(8)[1 - (1 - 2x)²] = (m)/(8)[1 - (1 - 4x + 4x²)] = (m)/(8)(4x - 4x²) = (m)/(2)(x - x²)

This is an inverted parabola (K ∝ x - x²) passing through x=0 and x=1, reaching a peak at x = 1/2. This matches Graph (1).

Pattern Recognition

The position oscillates purely within the boundary interval [0, 1]. Kinetic energy peaks perfectly at the equilibrium midpoint x = 1/2 where speed is maximum.

Chapter Mix

Class 11 Physics: Oscillations

Reference Study Guides

More Oscillations Previous-Year Questions — Page 2

Q42 jee_main_2026_28_january_evening Two Body Oscillator
As shown in the figure, a spring is kept in a stretched position with some extension by holding the masses 1 kg and 0.2 kg with a separation more than spring natural length and are released. Assuming the horizontal surface to be frictionless, the angular frequency (in SI unit) of the system is :
Two Body Oscillator diagram for Q42 - JEE Main 2026 Evening
Two masses attached to ends of a spring on a horizontal table.
  • A. 30
  • B. 27
  • C. 20
  • D. 5

Solution

Related Formula
ω = √((k)/(μ))

where μ is the reduced mass of the system given by:

μ = (m₁ m₂)/(m₁ + m₂)
Step 1: Calculate Reduced Mass

Given m₁ = 1 kg and m₂ = 0.2 kg.

μ = (1 × 0.2)/(1 + 0.2) = (0.2)/(1.2) μ = (1)/(6) kg
Step 2: Calculate Angular Frequency

Given spring constant k = 150 N/m.

ω = √((150)/(1/6)) = √(150 × 6) = √(900) ω = 30 rad/s
Pattern Recognition

For any two-body spring system free of external forces, always substitute the individual mass m with the reduced mass μ = (m₁ m₂)/(m₁ + m₂) in the standard oscillator formula ω = √(k/m).

Chapter Mix

Class 11 Physics: Oscillations

Q jee_main_2025_02_april_morning Superposition of SHMs
A particle is subjected to two simple harmonic motions as: x₁ = √(7) 5t~cm and x₂ = 2√(7) (5t + (π)/(3))~cm where x is displacement and t is time in seconds. The maximum acceleration of the particle is x × 10⁻²~ms⁻². The value of x is:
  • A. 175
  • B. 25√(7)
  • C. 5√(7)
  • D. 125

Solution

Related Formula
A = √(A₁² + A₂² + 2 A₁ A₂ φ) a = ω² A
Core Logic

Both SHMs share the same frequency ω = 5~rad/s with phase difference φ = (π)/(3). Amplitudes: A₁ = √(7)~cm, A₂ = 2√(7)~cm.

The combined amplitude is:

A = (√(7))² + (2√(7))² + 2(√(7))(2√(7)) ((π)/(3)) A = √(7 + 28 + 2(7)(2)((1)/(2))) = √(35 + 14) = √(49) = 7~cm

Converting to meters:

A = 0.07~m

The maximum acceleration is:

a = ω² A = (5)² × 0.07 = 25 × 0.07 = 1.75~ms⁻²

Equating to x × 10⁻²~ms⁻²:

1.75 = x × 10⁻² x = 175
Step 1: Final Conclusion

The value of x is 175.

Pattern Recognition

When superposing two SHMs of identical frequency, use the standard phasor addition formula to obtain the combined amplitude A. Then compute maximum velocity v = ω A or maximum acceleration a = ω² A directly.

Chapter Mix

Class 11 Physics: Simple Harmonic Motion

Q10 jee_main_2025_29_jan_evening Energy in Simple Harmonic Motion
Two bodies A and B of equal mass are suspended from two massless springs of spring constant k₁ and k₂ , respectively. If the bodies oscillate vertically such that their amplitudes are equal, the ratio of the maximum velocity of A to the maximum velocity of B is:
  • A. √((k₁)/(k₂))
  • B. k₁k₂
  • C. k₂k₁
  • D. k₂k₁

Solution

Related Formula
v = Aω ω = √((k)/(m))
Core Logic

The maximum velocity in vertical SHM happens at the mean equilibrium position and is given by v = Aω.

Given mA = mB = m and AA = AB = A:

vA = A ω₁ = A √((k₁)/(m)) vB = A ω₂ = A √((k₂)/(m))

Taking the ratio:

(vA)/(vB) = (ω₁)/(ω₂) = √((k₁)/(m))√((k₂)/(m)) = √((k₁)/(k₂))
Pattern Recognition

Since maximum velocity is directly proportional to angular frequency ω for equal amplitudes, and ω ∝ √(k), the velocity ratio directly yields the square root of the spring constant ratio.

Chapter Mix

Class 11 Physics: Oscillations

Q jee_main_2025_04_april_morning Simple Pendulum
Two simple pendulums having lengths l₁ and l₂ with negligible string mass undergo angular displacements θ₁ and θ₂, from their mean positions, respectively. If the angular accelerations of both pendulums are same, then which expression is correct?
  • A. θ₁l₂² = θ₂l₁²
  • B. θ₁l₁ = θ₂l₂
  • C. θ₁l₁² = θ₂l₂²
  • D. θ₁l₂ = θ₂l₁

Solution

Related Formula

Angular acceleration definition for a simple pendulum swinging at small angle θ:

α = -ω² θ

where:

ω = √((g)/(l)) ω² = (g)/(l)

Hence, the magnitude of angular acceleration is:

α = (g)/(l)θ
Core Logic

Given that angular accelerations are exactly identical in magnitude (α₁ = α₂):

(g)/(l₁)θ₁ = (g)/(l₂)θ₂
Step 1: Simplify Expression

Cancelling out the constant gravitational acceleration g:

(θ₁)/(l₁) = (θ₂)/(l₂) θ₁ l₂ = θ₂ l₁
Pattern Recognition

Angular acceleration scales inversely with length for a fixed angular displacement (α ∝ (θ)/(l)). To maintain identical angular accelerations, the ratio (θ)/(l) must remain constant, yielding the cross-multiplication relation θ₁ l₂ = θ₂ l₁.

Evaluation Rubric / Model Answer

Option D: θ₁l₂ = θ₂l₁

Chapter Mix

Class 11 Physics: Oscillations

More Oscillations Questions — jee_main_2025_24_jan_evening

Practice all Oscillations previous-year questions →

Rankbit System
JEE Physics: Waves (+15.5%) | Electrostatics: Concentric Shells (-29.7%) | Modern Physics: Photoelectric Clones (+34.2%) | Mathematics: Definite Integrals (+18.1%) | Chemistry: Coordination Splitting (-11.4%) | JEE Physics: Waves (+15.5%) | Electrostatics: Concentric Shells (-29.7%) | Modern Physics: Photoelectric Clones (+34.2%) | Mathematics: Definite Integrals (+18.1%) | Chemistry: Coordination Splitting (-11.4%)