JEE Main 2022 · 26 July · morning · Single correct · +4 / −1

When a particle executes Simple Hormonic Motion, the nature of graph of velocity as a function of displacement will be :

  1. (a) Circular
  2. (b) Elliptical
  3. (c) Sinusoidal
  4. (d) Straight line
Answer and solution

Answer (b) Elliptical

Solution

Physics sir · 3 steps

Eliminate time between x and v, and the equation that drops out is an ellipse.

  1. Write x and v. Take x = A sin ω t. Differentiating gives v = Aω cos ω t.
  2. Remove time. Use sin² ω t + cos² ω t = 1, with sin ω t = x/A and cos ω t = v/(Aω).

    x²/A² + v²/A²ω² = 1

  3. So. This is an ellipse with semi-axes A along x and Aω along v. The answer is (b).

The idea to keep. A graph of one quantity against another, with no time axis, needs time eliminated. In SHM, v against x and a against v both give ellipses, while a against x is a straight line.

Answer from the NTA final answer key. Solution by PrepWiser.

Study Simple Harmonic Motion

Asked about 130 times in JEE Main since 2020. This question is from 2022.