<p>Oh my god i am getting frustrated. In chapter 14 it says that calculate the amount of word done on 2 kg of water . delta T is 10.
How can anyone calculate that without the specific heat capacity of water given, which the book doesn't. Even though i know its 4.2, how would i know that the book takes it as 4.193 or something.
Second, Work done on a system is said to be negative, which is complete @@@@@@, it is actually positive.
Also, the forumla for internal energy is
delta U = delta Q + delta W
where work is done TO the system and Q is added TO the system, the books got that wrong in so many places.
Who writes such books.</p>
<p>I took regular physics last year... Work done by a system is positive, and work done onto the system is negative. The book is right.</p>
<p>but...... The mathematical statement of the first law is given by:
delta u = delta q "-" delta W</p>
<p>where dU is the infinitesimal increase in the internal energy of the system, δQ is the infinitesimal amount of heat added to the system, and δW is the infinitesimal amount of work done by the system on the surroundings</p>
<p>It depends on whether you interpret W as work done on the system or work done by the system.</p>
<p>wxmann, it's the other way around. If you do work on a system, you are increasing its internal energy, so W has to be positive if you are using dU = dQ + dW.</p>