A substance has a fixed volume. What else do you need to know to determine its state of matter?

If it can change shapes easily.

Explanation:

A fixed volume eliminates gas as a possible state of matter, therefore leaving liquid and solid.

If the substance can easily change shape, it is a liquid. If it cannot change shape, then it is a solid.

Another way to determine the state of matter is through particle movement.

If particles slip past each other, it is a liquid. If particles vibrate in place, it is a solid.

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.