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Asia-Pacific Forum
on Science Learning and Teaching, Volume 10, Issue 2, Article 3 (Dec., 2009) |
Appendix B
2nd interview question for spring semester
The work-energy principle
A rebounding block
A metal block of mass 3 kg is moving downward with speed 2m/s when the bottom of the block is 0.8 m above the floor (Figure B1). When the bottom of the block is 0.4 m above the floor, it strikes the top of a relaxed vertical spring 0.4 m in length. The stiffness of the spring is 2000 N/m.
Figure B1. A block Rebounds from a Vertical Spring (Chabay & Sherwood, 2002, p.199).
a) Choose your system and answer (b) and (c) according to your system.
b) The block continues downward. When the bottom of the block is 0.3 m above the floor, what is its speed?
c) What approximation did you make?
