if the breakers at a beach are separated by 5.0 m and hit shore with a frequency of 0.20 hz, with what speed are they traveling (in m/s)?

An inclined plane wrapped around a metal shaft is a a. lever b. screw c. pulley d. wedge

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.

If the chemical properties of a substance remain unchanged and appearance or shape of a substance changes it is called a ?