Verified Solution • 2025–26 Session moderate

QJEEM21Ph3130: JEE Main 2021 Physics - Class 11 JEEM21Ph3130 Solution: Given below is the plot of a potential energy function U(x) for …

Given below is the plot of a potential energy function U(x) for a system, in which a particle is in one dimensional motion, while a conservative force F(x) acts on it. Suppose that Emech = 8 J, the incorrect statement for this system is :

JEE Main 2021 (Online) 27th July Evening Shift Physics - Work Power & Energy Question 75 English
[ where K.E. = kinetic energy ]

Multiple Choice Options

  • A at x > x4 K.E. is constant throughout the region.
  • B at x < x1, K.E. is smallest and the particle is moving at the slowest speed.
  • C at x = x2, K.E. is greatest and the particle is moving at the fastest speed.
  • D at x = x3, K.E. = 4 J.

Step-by-Step Verified Solution

Emech. = 8J

(A) at x > x4

U = constant = 6J

K = Emech. −- U = 2J = constant

(B) at x < x1

U = constant = 8J

K = Emech −- U = 8 −- 8 - 0 J

Particle is at rest.

(C) At x = x2,

U = 0 ⇒\Rightarrow Emech. = K = 8 J

KE is greatest, and particle is moving at fastest speed.

(D) At x = x3

U = 4J

U + K = 8J

K = 4J

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