You wish to buy a new freezer for your basement. the primary use of the freezer will be to prepare ice for family parties. you have a very large family, with grandparents, parents, sisters, brothers, uncles, aunts, cousins, nephews, nieces, and grandchildren. as a result, family birthday parties are held every couple of weeks, and you need lots of ice for drinks. you want the freezer to convert 10.2 kg of water at 21.5°c to 10.2 kg of ice at −9.2°c in 2.00 h. but, in order to keep your electric bill down, you want the power rating of the freezer to stay below 100 w. from these requirements, you determine the minimum cop of the freezer that will satisfy your needs. (consider that the specific heat of water is 4,186 j/(kg · °c), the specific heat of ice is 2,090 j/(kg · °c), the latent heat of fusion of water is 3.33 ✕ 105 j/kg, and the latent heat of vaporization of water is 2.26 ✕ 106 j/kg.)

Abrake has a normal braking torque of 2.8 kip in and heat-dissipating cast-iron surfaces whose mass is 40 lbm. suppose a load is brought to rest in 8.0 s from an initial angular speed of 1600 rev/min using the normal braking torque; estimate the temperature rise of the heat dissipating surfaces.

Which one from below is not one of the reasons of planning failures? (clo3) a)-planner is careless. b-planner spend less time in the field but more time on the desk c)-planner is not qualified d)-planner does not have sufficient time to properly plan

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?