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NEET2026PhysicsChapterActual

A particle moves along a straight line such that the time t and position x are related by the equation t = 3x^2 - 4x . If v represents the instantaneous velocity of the particle, which of the following expressions gives its acceleration?

Options

  1. A-6v^2
  2. B-6v^3
  3. C+6v^3
  4. D-3v^3

Correct answer

B. -6v^3

Step-by-step solution

Given t = 3x^2 - 4x Differentiating with respect to x : dt dx = 6x - 4 The instantaneous velocity v is given by: v = dx dt = 1 6x - 4 The acceleration a is given by: a = dv dt = v dv dx Differentiating v with respect to x : dv dx = d dx (6x - 4)⁻¹ = -1(6x - 4)⁻² 6 = -6(6x - 4)⁻² Since v = (6x - 4)⁻¹ , we have (6x - 4)⁻² = v^2 dv dx = -6v^2 Substituting this into the expression for acceleration: a = v(-6v^2) = -6v^3 Answer: -6v^3

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