Respuesta :
Given:
• Forces from object A:
Work on object B = 10 J
Work on object C = -5 J
• Forces from the environment:
Work on object B = 4 J
Work on object C = 8J
Given that the forces of objects B and C do not interact,
Let's find ∆K_tot and ∆U_nit.
When:
• (a). Objects A, B, and C are defined as separate systems.
Since object A is stationary, we have: ∆KA = 0 J
[tex]\begin{gathered} \Delta K_B=10\text{ J + 4 J = 14 J} \\ \\ \Delta K_C=-5\text{ J + 8 J = 3 J} \\ \\ \Delta K_{tot}=0J+14J\text{ + 3 J = 17 J} \end{gathered}[/tex]ii). Since all objects are defined as separate systems, all forces are external to the system.
Therefore, the change in U = 0
[tex]\Delta K_{unit}=0\text{ }[/tex]• (b). one system is defined to include objects A, B, and C and their interactions?
Here, if one system is defined to include the objects and their interactions, we have:
[tex]\Delta K_{tot}=14J+3J\text{ = 17 J}[/tex]Also, for the change in U, we have:
[tex]\Delta K_{unit}=-(10-5)=-10J+5J=-5J[/tex]ANSWER:
(a). ∆Ktot = 17 J
∆Kunit = 0 J
(b). ∆Ktot = 17 J
∆Kunit = -5 J
