Physics 1: Matter And Energy - Section 2 - Internal Energy - 2.1.3

Front 1

Internal energy, U, is:

Back 1

The energy in a system arising from the relative positions and interactions of its parts.

Front 2

Be wary:

1) Temperature and internal energy?

- Temperature?

- Internal Energy?

Back 2

1) Not the same.

- Temperature: The AVERAGE microscopic energy of the particles.

- Internal energy: The sum of the microscopic energy of the particles.

Front 3

E.g. What would have the greater internal energy:

1) 1kg of iron @ 300K

2) 2kg of iron @ 300K

Back 3

2) because the temperature, so average energy, is the same. However there are more particles in 2kg than in 1kg so the 2kg of iron has a greater internal energy.

Front 4

Internal energy:

1) Compared to Ek & Ep?

Back 4

1) They both consider what an object does/could do - 'U' considers what an object is doing within itself.

Front 5

Calculations for internal energy:

1) We only need to calculate for?

Back 5

1) Changes in internal energy.

Front 6

Although we don't need to calculate U:

1) We need to know that?

Back 6

1) U can never be less than or equal to 0. It tends towards 0 but never reaches it as there is always some internal energy.