sending signals to muscles, causing them to contract, or to glands, causing. them to produce secretions. Neurons, or nerve cells, carry out the functions of the nervous system by. conducting nerve impulses.
Best Answer: Specific Heat is the energy required to raise EACH gram of a material by 1C. This is expressed in J/gC. The temperature change is 82.1C - 30.7C = 51.4C. The Aluminum weighs, not 1g, but 625g. m x c x Î´T = Q 29.5g x 0.45J/g/Â°C x (40 - 25Â°C) Î´T = 199.125 Joules (= 0.199kJ) of heat absorbed. (you can say 0.200kJ) If 8.4kJ was used as in your initial statement, to raise the temp. by 5Â°C, the mass of iron must have been much greater than 29.5g. or, 8.4kJ is an error. 29.5 x 0.45 x 5 = 66.4 kJ.
Since equipment for welding aluminum needs to operate at higher capacities, many feel that preheat helps eliminate equipment limitations, but this is not the case. Aluminum has a low melting point -- 1200Â° F compared to 2600Â° F to 2700Â° F for steel.herefore, if the operator doesn't perform post-weld heat treatments after welding, the area around the weld will become significantly weaker than the rest of the aluminum-by as much as 30 to 40 percent.