Question

Which object in the following pairs has a greater total internal energy, assuming that the two objects in each pair are in thermal equilibrium?
(a) a metal knife in thermal equilibrium with a hot griddle.

hot griddlemetal knife   

(b) a 1 kg block of ice at -15°C or seven 175 g ice cubes at -15°C

seven ice cubes1 kg block of ice   

What reasoning below justifies your answers to parts (a) and (b)?

For all temperatures, the object with smaller mass has a greater internal energy.For equal temperatures, the object with smaller mass has a greater internal energy.    For all temperatures, the object with larger mass has a greater internal energy.For equal temperatures, the object with larger mass has a greater internal energy.

Which object in the following pairs has a higher temperature if both have the same internal energy?
(a) a metal knife and a hot griddle

metal knifehot griddle

(b) a 1 kg block of ice or seven 110 g ice cubes

1 kg block of iceseven ice cubes   

What reasoning below justifies your answers to parts (a) and (b)?

For all internal energies, the object with smaller mass has a higher temperature.For equal internal energies, the object with larger mass has a higher temperature.    For equal internal energies, the object with smaller mass has a higher temperature.For all internal energies, the object with larger mass has a higher temperature.

Answer 1

(a) Hot Griddle

Two objects with the same temperature and the same materials, the more massive one will have the greater internal energy

therefore, the griddle is probably more massive than the knife so it is likely to have more internal energy.

(b) Seven 175g cubes

seven 175g cubes = 7*0.175 kg = 1.225 kg > 1kg

, so Seven 175g has more total internal energy as it is more massive.

Reasoning:

For equal temperatures, the object with larger mass has a greater internal energy.

For equal internal energies, the object with smaller mass has a higher temperature. So:

a.) metal knife

b.) 1kg ice cube

Reasoning:

For equal internal energies, the object with smaller mass has a higher temperature.