Question

what should be the speed of the body so that its K.E becomes half of its initial K.E?

Answer 1

Hey mate


When the initial velocity of the body is v.

$ke = \frac{1m {v}^{2} }{2}$
Now
$ke2 = \frac{1}{2} \times \frac{1m { {vi}^{} }^{2} }{2}$

[Vi is the new velocity]

$\frac{ke1}{ke2} = \frac{ \frac{1m {v}^{2} }{2} }{ \frac{1m {vi}^{2} }{4} }$