A system gains 473J of kinetic energy while losing 271J of potential energy. The thermal energy increases by 127J .
Use an energy bar chart of this process to find the external work Wext.
To find the external work, we need to use an energy bar chart to represent the different forms of energy involved in the process.
An energy bar chart is a visual representation that shows the initial and final energies of a system, as well as any energy transfers or transformations that occur in between.
Let's break down the given information into different forms of energy and use the energy bar chart to accurately represent them.
Initial Energy:
- Kinetic energy (Ki)
- Potential energy (Pi)
- Thermal energy (Ti)
Final Energy:
- Kinetic energy (Kf)
- Potential energy (Pf)
- Thermal energy (Tf)
Given information:
- Change in kinetic energy (ΔK) = +473 J
- Change in potential energy (ΔP) = -271 J
- Change in thermal energy (ΔT) = +127 J
Now, let's represent this information on the energy bar chart:
Initial Energy:
Ki + Pi + Ti
Final Energy:
Kf + Pf + Tf
Energy Transfers/Transformations:
- ΔK = Kf - Ki (positive value)
- ΔP = Pf - Pi (negative value)
- ΔT = Tf - Ti (positive value)
From the given information, we know the following equations:
ΔK = +473 J
ΔP = -271 J
ΔT = +127 J
Using these equations, we can now determine the final energy values:
Kf - Ki = +473 J
(Pf - Pi) = -271 J
(Tf - Ti) = +127 J
Now, let's focus on the kinetic energy:
Kf - Ki = +473 J
To solve for Kf, we can rearrange the equation:
Kf = Ki + 473 J
Next, let's focus on the potential energy:
(Pf - Pi) = -271 J
To solve for Pf, we can rearrange the equation:
Pf = Pi - 271 J
Finally, let's focus on the thermal energy:
(Tf - Ti) = +127 J
To solve for Tf, we can rearrange the equation:
Tf = Ti + 127 J
Now we have the final energy values:
Kf = Ki + 473 J
Pf = Pi - 271 J
Tf = Ti + 127 J
To find the external work, Wext, we can use the principle of conservation of energy:
Wext = ΔK + ΔP + ΔT
Substituting the given values:
Wext = (+473 J) + (-271 J) + (+127 J)
Wext = +329 J
Therefore, the external work, Wext, is +329 J.