Question

The jet plane starts from rest at `s =0` and is subjected to the acceleration shown. Determine the speed of the plane when it has travelled 60 m.

A. `46.47 m//s`
B. `36.47 m//s`
C. `26.47 m//s`
D. `16.47 m//s`

Answer 1

Correct Answer - A
`a=(dv)/(ds)v implies int_(0)^(S)a.ds=int_(u)^(v)v.dv=v^(2)-u^(2)`
`implies"Area under" a~s "curve"=v^(2)-u^(2)`
`implies((1)/(2)xx150xx22.5)-(1)/(2)(90xx13.5)=v^(2)-0`
`impliesv^(2)=75xx22.5-45xx13.5`
`impliesv=sqrt(75xx22.5-45xx13.5)implies46.47`