A cubical box of mass 10 \mathrm{~kg} with edge length 5 \mathrm{~m} is free to move on a frictionless horizontal surface. Inside is a small block of mass 2 \mathrm{~kg}, which moves without friction inside the box. At time t=0, the block is moving with velocity 5 \mathrm{~m} / \mathrm{s} directly towards one of the faces of the box, while the box is initially at rest. The coefficient of restitution for any collision between the block and box is 90 \%, meaning that the relative speed between the box and block immediately after a collision is 90 \% of the relative speed between the box and block immediately before the collision. After 1 minute, the block is a displacement x from the original position. Which of the following is closest to x ?
Answer Choices
A. 0 \mathrm{~m}
B. 50 \mathrm{~m}
C. 100 \mathrm{~m}
D. 200 \mathrm{~m}
E. 300 \mathrm{~m}
