Two shuffleboard disks of equal mass, one orange, and the other yellow are involved in
an elastic collision. The yellow disk is initially
at rest and is struck by the orange disk moving
initially to the right at 5.38 m/s. After the
collision, the orange disk is at rest.
What is the velocity of the yellow disk after
the collision?
Answer in units of m/s.

Asheet of steel 1.5 mm thick has nitrogen atmospheres on both sides at 1200oc and is permitted to achieve a steady-state diffusion condition. the diffusion coefficient for nitrogen in steel at this temperature is 6 x 10- 11 m2 /s, and the diffusion flux is found to be 1.2 x 10-7 kg/m2 -s. also, it is known that the concentration of nitrogen in the steel at the high-pressure surface is 4 kg/m3 . how far into the sheet from this high-pressure side will the concentration be 2.0 kg/m3 ? assume a linear concentration profile.