If w is positive, what happened to the volume?

If w is positive, what happened to the volume?

• A. Volume increased
• B. Volume decreased
• C. Temperature increased
• D. Pressure remained constant

Answer: (B)

Positive work means energy is being transferred to the system as work. For a gas, the work is related to volume change by w = -P_ext ΔV. If the volume decreases (ΔV is negative), the product -P_ext ΔV becomes positive, so w is positive. That tells you the process involved compression, i.e., the volume has decreased. Temperature or pressure aren’t fixed just by the sign of w; they depend on heat exchange and the specifics of the process, but the key takeaway is that positive work indicates the system was compressed and its volume shrank.

Positive work means energy is being transferred to the system as work. For a gas, the work is related to volume change by w = -P_ext ΔV. If the volume decreases (ΔV is negative), the product -P_ext ΔV becomes positive, so w is positive. That tells you the process involved compression, i.e., the volume has decreased. Temperature or pressure aren’t fixed just by the sign of w; they depend on heat exchange and the specifics of the process, but the key takeaway is that positive work indicates the system was compressed and its volume shrank.