QJEEM25Ph5e40: JEE Main 2025 Physics - Class 11 JEEM25Ph5e40 Solution: Given below are two statements. One is labelled as Assertion…
Given below are two statements. One is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): 
Three identical spheres of same mass undergo one dimensional motion as shown in figure with initial velocities . If we wait sufficiently long for elastic collision to happen, then , will be the final velocities.
Reason (R): In an elastic collision between identical masses, two objects exchange their velocities.
In the light of the above statements, choose the correct answer from the options given below:
Multiple Choice Options
- A Both (A) and (R) are true but (R) is NOT the correct explanation of (A)
- B Both (A) and (R) are true and (R) is the correct explanation of (A)
- C (A) is false but (R) is true
- D (A) is true but (R) is false
Step-by-Step Verified Solution
We know that two bodies of the same mass exchange their velocities after an elastic head-on collision.
Given, initially,
Here,
first A will collide with B and the velocities will be exchanged.
i.e. now, V = 2 m/s and V = 5 m/s and V = 4 m/s
As V_B > V_C
So, B will collide and exchange the velocities with C.
So, m/s. and m/s.
Hence, finally,
So, A is false but R is true.