Two identical arrows,one with twice the kinetic energy of the other,are fired into a hay bale.The faster arrow will penetrate
A)the same distance as the slower arrow.
B)twice as far as the slower arrow.
C)four times as far as the slower arrow.
D)more than four times as far as the slower arrow.
E)none of these

Question

Quizplus · Accepted Answer

The kinetic energy of an object is directly proportional to the square of its velocity. Therefore, if one arrow has twice the kinetic energy of the other, it must have a velocity that is the square root of 2 times greater. Since both arrows have the same mass, the faster arrow will have twice the momentum of the slower one. When the arrows hit the hay bale, they will experience an equal and opposite force that will slow them down. Because the faster arrow has more momentum, it will take longer to come to a stop and will penetrate the hay bale twice as far as the slower arrow.

Two Identical Arrows,one with Twice the Kinetic Energy of the Other,are