Question

s is proportional to (v–1)2 ; When s=8; v=3; find v when s=2;

Answer 1

let k be the proportionality constant

$\longmapsto\tt{s = k(v-1)^2}$

Now

$\longmapsto\tt{s = 8 \: when \: v = 3}$

$\longmapsto\tt{ie 8 = k(3-1)^2 , 8 = 4k , k = 2}$

$\longmapsto\tt{(a) when v = 4 , s = k(4-1)^2 = 2*9 = 18}$

$\longmapsto\tt{(b) when s = 2 , 2 = 2(v-1)^2}$

$\longmapsto\tt{, (v-1)^2 = 1 taking \: underoot \: on \: both sides \: we get v-1 = 1 , v =2}$

this is prolly right