I have some physics questions here pls help me to answer this. 1.Suppose 129 J o
ID: 1391254 • Letter: I
Question
I have some physics questions here
pls help me to answer this.
1.Suppose 129 J of work is done on a system and 75.5 cal is extracted from the system as heat. In the sense of the first law of thermodynamics, what are the values (including algebraic signs) of (a) W (here W represents the work done by the gas), (b) Q, and (c) ?Eint?
W = ??? J by the gas
Q = ???J
?Eint = ???? J
2. Calculate the specific heat of a metal from the following data. A container made of the metal has a mass of 3.3 kg and contains 12 kg of water. A 1.2 kg piece of the metal initially at a temperature of 170
Explanation / Answer
Work done on the system W = -129 J
heat Q = -75.5 cal
= -75.5 x 4.186 J
= - 316 J
From first law of thermodynamics,Q = E + W
From this E = Q -W
= -187 J
(2).Mass of metal container m = 3.3 kg
mass of water M = 12 kg
mass of piece m ' = 1.2 kg
initially at a temperature of piece t = 170