Posted by rahul patel on Monday, November 21, 2011 at 8:47pm.
the kinetic energy of moving body ids directly praportional to its mass and the square of its speed.if the mass of a bullet is halved by what factor must its speed be increased to have the same kinetic energy as before?

Math  Steve, Tuesday, November 22, 2011 at 5:41am
E = k * m * v^2
If we halve the mass, now we have
E' = k * m/2 * v^2 = E/2
In order to get E' = E, we need a new velocity, v'
E' = k * m/2 * v'^2
and we see that
v'^2 must be 2v^2
so, v' = v√2