JEE Main Physics Class 11 Work, Energy and Power Part 1 Questions

According to the question, all collisions are perfectly inelastic, so after the final collision, all blocks are moving together.
Let the final velocity be v', using momentum conservation
mv=16mv′⇒v′=

v

16

Now initial energy Ei=

1

2

mv2
Final energy: Ef=

1

2

×16m×(

v

16

)2=

1

2

mv2

16

Energy loss : Ei−Ef=

1

2

mv2−

1

2

m

v2

16

⇒

1

2

mv2[1−

1

16

]⇒

1

2

mv2[

15

16

]
The total energy loss is P% of the original energy.
∴%P=

Energy loss

Original energy

×100
=

1 2 mv2[ 15 16 ]

1 2 mv2

×100=93.75%