Stephanie and her family went to the pumpkin patch to pick out the perfect pumpkin to carve for Halloween. Stephanie picked out her favorite pumpkin, put it in a wagon, and started pulling her pumpkin and wagon out of the field. All of a sudden, the wagon stopped rolling and Stephanie could not move her pumpkin any further. She knew there was an opposing force holding it in place. All of the following could be the opposing force except for which one? A) An upwards hill B) A small breeze blew C) A stick lodged in the axle D) A rock getting stuck under the tire

A3-mm-thick panel of aluminum alloy (k 177 w/m-k, c 875 j/kg-k and ? = 2770 kg/m) is finished on both sides with an epoxy coating that must be cured at or above t,-150°c for at least 5 min. the production line for the curing operation involves two steps: (1) heating in a large oven with air at ts,0-175°c and a convection coefficient of h, 40 w/m2. k, and (2) cooling in a large chamber with air at 25°c and a con- vection coefficient of he 10 w/m2.k. the heating portion of the process is conducted over a time interval te which exceeds the ime required to reach 150°c by 5 min (h = r + 300 s). the coating has an emissivity of ? = 0.8, and the temperatures of the oven and chamber walls are 175 and 25°c, respectively. if the panel is placed in the oven at an initial temperature of 25°c and removed from the chamber at a safe-to-touch tempera ture of 37°c, what is the total elapsed time for the two-step curing operation?