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What is the defining feature of a conservative force?
AThe work it does is always positive
BThe work it does is path independent
CThe work it does is always zero
DThe work it does depends on speed
Answer & Solution
Correct answer: B. The work it does is path independent
1. Push a ball up three different slopes to the same height and gravity does the same work each time.
2. Only the change in height matters, not how long or steep the route was.
3. A force with that property is called conservative, and a potential energy can be defined for it.
4. Friction fails the test because a longer path costs more energy, so friction is non conservative.
5. The work done by gravity is negative going up and positive coming down, so it is not always positive.
_Source: Siyavula Physical Sciences Grade 12 (Everything Science, CC BY 4.0), Chapter 5: Work, energy and power_
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