Compare the heat loss from an insulated and an uninsulated copper pipe (k =400 W/m K) under the following conditions. The pipe has an internal diameter of 10 cm and an external diameter of 12 cm. The inside surface temperature of the pipe is at 110°C. The pipe is located in a space where all possible outside surface temperature of material was maintained at 30°C. The insulation available to reduce heat losses is 5 cm thick and its conductivity is 0.20 W/m K. If the furnace for heating the fluid in the pipe operating at an efficiency of 85% using natural gas priced at Cg = Php 1.00/MJ, what is the daily cost of heat loss per meter of pipe?

Ice of mass 10.0 kg at 0.00° C is placed in an ice chest. The ice chest has 2.00 cm thick walls of thermal coductivity 1.00 x 10^-5 kcal/s-m-C° and a surface area of 1.30m^2. (a) How much heat must be absorbed by the ice before it melts? (b) If the outer surface of the ice chest is at 30.0° C, how long will it take for the ice to melt?

The thermal conductivities of human tissues vary greatly. Fat and skin have conductivities of about 0.20 W/m · K and 0.020 W/m · K respectively, while other tissues inside the body have conductivities of about 0.50 W/m · K. Assume that between the core region of the body and the skin surface lies a skin layer of 1.0 mm, fat layer of 0.50 cm, and 3.2 cm of other tissues. (a) Find the R-factor for each of these layers, and the equivalent R-factor for all layers taken together, retaining two digits. Rskin      m2 · K/W Rfat      m2 · K/W Rtissue      m2 · K/W R      m2 · K/W (b) Find the rate of energy loss when the core temperature is 37°C and the exterior temperature is 0°C. Assume that both a protective layer of clothing and an insulating layer of unmoving air are absent, and a body area of 2.0 m2. W

A playground slide has a height of 4.5m amd is frictionless. A 30 kg child pushes off from the top of the slide so that they have a speed of 5.5 m/s at the fop of Hhe slide. a) What's the child's speed at the bottom of the slide? b) After the bottom of the slide, child skids along a rough patch of ground If the rough patch is 2.2 m the friction an the child when they veach the end of the rough patoh? c) Imagine the playgronnd had a spring (K= 755 N/m) at the end of the patch. If the child were to collide, how muuh wonla they Compress before returning to rest? that has a coefficient of friction Mk= 2.5 long, how mnch work is done by