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The potential energy of a system increases if work is done
A
Upon the system by a conservative force
B
Upon the system by a non-conservative force
C
By the system against a conservative force
D
By the system against a non-conservative force
Detailed Solution
Potential energy is defined only for conservative forces, by the relation $\Delta U = -W_{conservative}$
When the system does work against a conservative force, the work done by that conservative force is negative.
Then $\Delta U = -(\text{negative}) = $ positive, i.e., the potential energy increases (for example, raising a body against gravity or compressing a spring).
When a conservative force does work upon the system, U decreases; work involving non-conservative forces does not get stored as potential energy.
Hence the potential energy increases when work is done by the system against a conservative force.
When the system does work against a conservative force, the work done by that conservative force is negative.
Then $\Delta U = -(\text{negative}) = $ positive, i.e., the potential energy increases (for example, raising a body against gravity or compressing a spring).
When a conservative force does work upon the system, U decreases; work involving non-conservative forces does not get stored as potential energy.
Hence the potential energy increases when work is done by the system against a conservative force.