Distance=average velocity x time =((12+8)/2) x 3 =30m

The models are used to represent what you are studying in this case would be a planet. A model of Saturn and its rings and the moons surrounding it would be fantastic to look at when you have no way of going there

This is a lens<span> in which both surfaces are curved so that a beam of light passing through it is brought to a point or focus.hope this helps</span>

**Answer:**

w=255

**Explanation:**

The change in internal energy is given by the first law:

ΔE = Q - w

where ΔE is the change in internal energy of the system

q is the heat added to the system

w is the work done *by* the system on the surroundings

So, for the first phase of this process:

ΔE = Q - w

Q=160J

w=309J

ΔE = 160J - 309J = -149J

To bring the system back to its initial state after this, the internal energy must change by +149J (the system myst gain back the 149 J of energy it lost). We are told that the system loses 106 J of heat in returning to its initial state, so the work involved is given by:

ΔE = Q - w

+149J = -106J - w

255J = -w

w = -255J