A bullet is fired through a board 10 cm thick in such a way that the bullet's line of motion is perpendicular to the face of the board. If the initial speed of the bullet is 400 m/s and it emerges from the other side of the board with a speed of 300 m/s, what is the total time the bullet is in contact with the board? Label your answer. To write an exponent in your answer, please type it like this: 10^3.
