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Michael Ngo
- 8
- 0
Homework Statement
I've encountered an answered problem in this book titled, "Physics for Scientists and Engineers with Modern Physics, 9th Ed" by Serway at page 187.
So there is a spring which is hung vertically.
1. The first condition was the spring at an equilibrium state (ΔX=0)
2. The second condition, a block with a mass of 0.55 kg was attached at the lower end of the vertical spring and the spring stretched 2.0 cm
The work done by the spring was around -0.054 J and the work done by gravity on the object was around 0.11 J
So here's my question :
1. Why is the work done by the spring and the work done by gravity are not the same amount ? If the work done by the spring is negative and the work done by gravity is positive, should it not counter each other to achieve an equilibrium state or not moving at all ?
2. What does the negative and positive meant on the works ? Does it refer to direction (up or down) ?
3. I also found a formula for work by external agent. Is gravity also included as an external agent ? If not, why ? Isn't gravity came from outside of the block ?
Homework Equations
Not needed
The Attempt at a Solution
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