The surface of a steel gear of 1022 steel (0.22 wt % C ) is to be gas-carburized at 927 oC. Calculate the time necessary to increase the carbon content to 0.3 wt% at 0.015 in. below the surface of the gear. Assume the carbon content of the surface to be 1.20wt%. D (C in iron ) at 927 oC = 1.28 x 10-11 m2/s. The answer should have one decimal of accuracy and be in minutes.

Asmall metal bar, whose initial temperature was 10° c, is dropped into a large container of boiling water. how long will it take the bar to reach 70° c if it is known that its temperature increases 2° during the first second? (the boiling temperature for water is 100° c. round your answer to one decimal place.) sec how long will it take the bar to reach 98° c? (round your answer to one decimal place.)

Tafari worked one summer on a ship that set weather buoys in the ocean. he watched how one of the buoys moved in the water. describe which parts of the wave would cause the buoy to bob up and down. which wave property determined how fast the buoys bobbed in the water? he observed that when the wind blew harder, the ocean waves were larger, and the buoys moved away from the ship. what effect, if any, did the waves have on how far the buoys moved? explain your answer.

What is friction? how does it affect the motion of an object?