A body covers 100 cm in first 2 seconds and 128 cm in the next four seconds moving with constant acceleration. Find the velocity of the body at the end of 8 sec ?

Explanation

In first 2 seconds
`100=2u+1/2a.4`…(1)
In first 6 seconds
`228=6u+1/2 a.36`…(2)
(1) x 3 -(2) gives 72 =-12 a
`a=-6 "cm/s"^2` …(3)
`100=2u-1/2xx6xx4`
2u=112
u=56 cm/s ….(4)
Now velocity of body at the end of 8 sec is
V=u+at =56-6 x 8
`therefore` V=8 cm/s