Physics, asked by StrongGirl, 9 months ago

JEE MAINS PHYSICS QUESTION SEPTEMBER 2020

Attachments:

Answers

Answered by abhi178
0

A body of mass m moving with velocity v collides with shown masses respectively. find loss in kinetic energy after the last collision. consider all collision completely inelastically. ?

solution : as collisions are being considered completely inelastically.

so after final collision, all bodies move together. let final velocity of system of bodies is v'

from conservation of linear momentum.

initial momentum = final momentum

⇒mv = (m + m + 2m + 4m + 8m)v'

⇒v/16 = v'

now loss in kinetic energy , ∆K = initial kinetic energy - final kinetic energy

= 1/2 mv² - 1/2 (16m)(v/16)²

= 1/2 mv²[1 - 1/16]

= 1/2 mv² (15/16)

now percentage loss in kinetic energy after the last collision = ∆K/K_i × 100

= 1/2 mv²(15/16)/1/2 mv² × 100

= (15/16) × 100

= 15 × 25/4

= 375/4

= 93.75

Therefore the percentage loss in kinetic energy after the last collision is 93.75 %

Similar questions