<p>A bullet when fired at a target with a velocity of 100&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>m</mi><msup><mi>s</mi><mrow><mo>-</mo><mn>1</mn></mrow></msup></math>, penetrates one metre into it. If the bullet is fired with the same velocity at a simple target with a thickness 0.5 metre, then it will emerge from it with a velocity of&nbsp;</p>