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?

Answer 1

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