Question

A. What is the change in internal energy for each of the following situations? q = 7.9 J out of the system and w = 3.6 J done on the system q = 1.5 J into the system and w = 7.5 J done on the system

Answer 1

Answer:
`-4.3\ J,\ 9\ J`

Step-by-step explanation:

Given

(a)

Heat transfer
`Q=-7.9\ J\quad \text{taken}`

Work done
`W=-3.6\ J\quad \text{on the system}`

Change in the internal kinetic energy is

`\Delta U=Q-W\\\Rightarrow \Delta U=-7.9-(-3.6)\\\Rightarrow \Delta U=-4.3\ J`

(b)

Heat transfer
`Q=1.5\ J\quad \text{given}`

Work done
`W=-7.5\ J\quad \text{on the system}`

Change in the internal kinetic energy is

`\Delta U=Q-W\\\Rightarrow \Delta U=1.5-(-7.5)\\\Rightarrow \Delta U=9\ J`