Cuatro contenedores idénticos tienen la misma cantidad de gas helio a la misma temperatura inicial. Los recipientes también cuentan con un émbolo móvil que no permite que el helio escape. Cada muestra de gas sigue un proceso distinto como se describe a continuación: Muestra 1: 500 J de calor salen del gas y este realiza 300 J de trabajo. Muestra 2: 500 J de calor entran al gas y este realiza 300 J de trabajo. Muestra 3: 500 J de calor salen del gas y se hace un trabajo de 300 J sobre él. Muestra 4: 500 J de calor entran al gas y se hace un trabajo de 300 J sobre él.

1)  ΔE = -800 J, 2) ΔE = 200 J, 3)  ΔE = -200 J, 4) ΔE = 800 J

Explanation:

For this exercise let's use the first law of thermodynamics

          ΔE = Q + W

Where we will apply this expression to several cases

1) output Q = 500 J and does work of W = 300 J.

The two processes involve an energy output

         ΔE = - 500 - 300

         ΔE = -800 J

Therefore, the internal energy of the gas decreases by this amount,

2) enter Q = 500J and do work of W = 300 J

         Positive heat is added and does negative work

         ΔE = 500 - 300

         ΔE = 200 J

3) they leave Q = 500 J and do (work on the gas) W = 300J

negative heat and positive work come out

          ΔE = -500 + 300

          ΔE = -200 J

4) heat enters Q = 500 J, work on gas W = 300 J

both positive

         ΔE = 500 + 300

         ΔE = 800 J

i had this question and the answer was 3.15 miles.

martina travels from school to her mom's office. from there, she walks to school. after school, she walks to the library and then to a friends house before finally ending back at home. find martina's total distance traveled.

a) 0 miles  

b) 0.4 miles  

c) 1 mile  

d) 3.15 miles