A 0.175 kg softball is pitched horizontally at 26 m/s. the ball moves in the opposite direction at 38 m/s after it is hit by the bat. 1. what is the change in momentum?
2. what is the impulse delivered by the bat?
3. if the bat and ball are in contact for 0.80 seconds, what is the average force that the bat applies to the ball?

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.