mv=(m+m)v′
(m+m)v′=(m+m+M)vf
∴ final velocity vf=2m+Mmv
Initial energy =21mv2
Final energy =21(2m+M)(2m+Mmv)2
Given that 6521mv2=21mv2−21(2m+M)(2m+Mmv)2
121mv2=21(2m+M)m2v2
6m=2m+M
mM=4
Three blocks A, B and C are lying on a smooth horizontal surface, as shown in the figure. A and B have equal masses, m while C has mass M. Block A is…
JEE Main 2019 — Physics Mechanics
2019mcqmedium
Three blocks A,B and C are lying on a smooth horizontal surface, as shown in the figure. A and B have equal masses, m while C has mass M. Block A is given an initial speed v towards B due to which it collides with B perfectly inelastically. The combined mass collides with C, also perfectly inelastically . 65th of the initial kinetic energy is lost in the whole process. What is the value of M/m?
Official previous-year question
Held on 9 Jan 2019 · Verified 6 Jul 2026.
Options
- A
3
- B
4
- C
5
- D
2
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