Question

A body starts from rest and moves with uniform acceleration. What is the ratio of kinetic energies at the end of 1st , 2nd and 3rd seconds of its journey ?

Answer 1

Answer:

1:4:9

Explanation:

kinetic energy (ek) = 1/2 mv^2

ek is directly proportional to v^2 ........ 1

after 1st sec v=at (as u=0)

as v directly proportional to t.......... 2

from 1 and 2 ek directly proportional to t^2

so 1st:2nd:3rd=1^2:2^2:3^2=1:4:9