waecmaths question:
Make u the subject of the formula, $E=\frac{m}{2g}({{v}^{2}}-{{u}^{2}})$
Option A:
$\sqrt{{{v}^{2}}-\tfrac{2Eg}{m}}$
Option B:
$\sqrt{\tfrac{{{v}^{2}}}{m}-\tfrac{2Eg}{4}}$
Option C:
$u=\sqrt{v-\tfrac{2Eg}{m}}$
Option D:
$u=\sqrt{\tfrac{2{{v}^{2}}Eg}{m}}$
waecmaths solution:
$\begin{align} & E=\frac{m}{2g}({{v}^{2}}-{{u}^{2}}) \\ & \frac{2gE}{m}={{v}^{2}}-{{u}^{2}}\text{ }\!\!\{\!\!\text{ Multiply both sides by }\tfrac{2g}{m}\} \\ & {{u}^{2}}={{v}^{2}}-\frac{2gE}{m} \\ & u=\sqrt{{{v}^{2}}-\frac{2gE}{m}} \\\end{align}$
maths year:
maths topics: