If a man speeds up by $1ms^{- 1}$, his KE increase by 44%. His original speed in $ms^{- 1}$ is

Question

Dr. Abubacker · Accepted Answer

(c) $E_{1} = \frac{1}{2}mv^{2}$
$E_{2} = \frac{1}{2}m(v + 1)^{2}$
$\frac{(E_{2} - E_{1})}{E_{1}} = \frac{\frac{1}{2}m\lbrack(v + 1)^{2} - v^{2}\rbrack}{\frac{1}{2}mv^{2}} = \frac{44}{100}$
On solving, we get $v = 5ms^{- 1}$

Q. If a man speeds up by $1ms^{- 1}$, his KE increase by 44%. His original speed in $ms^{- 1}$ is

Explanation

Reviewed by Dr. Abubacker

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