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Physics Question 91 – AP-EAMCET 2026

In SHM, velocity leads displacement by

In Simple Harmonic Motion, different physical quantities like displacement, velocity, and acceleration oscillate with the same angular frequency but have different phase relationships.

Step 1: Define Displacement in SHM✦ Active

The displacement of a particle undergoing Simple Harmonic Motion (SHM) can be represented by a sinusoidal function. A common form is:

x(t)=Asin(ωt)

where A is the amplitude, ω is the angular frequency, and t is time.

Step 2: Derive Velocity from Displacement○ Expand

Velocity (v) is the time derivative of displacement (x). Differentiating the displacement equation with respect to time, we get:

v(t)=dxdt=ddt(Asin(ωt))=Aωcos(ωt)
💡 Teacher's Secret Hint

Remember that the derivative of sin(at) is acos(at) and the derivative of cos(at) is asin(at).

Step 3: Compare Phases of Velocity and Displacement○ Expand

To compare the phase of velocity with that of displacement, we need to express the velocity function in terms of a sine function. We use the trigonometric identity cos(θ)=sin(θ+π2) or cos(θ)=sin(θ+90).

v(t)=Aωcos(ωt)=Aωsin(ωt+90)

Comparing the phase of x(t)=Asin(ωt) with v(t)=Aωsin(ωt+90), we can see that the phase of velocity is 90 greater than the phase of displacement. Therefore, velocity leads displacement by 90.

💡 Teacher's Secret Hint

A positive phase shift (e.g., +90) means the quantity 'leads' or occurs earlier in the cycle compared to the reference quantity.

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