Tutorial details

Section I: Relating work and changes in energy

Students examine two different systems involving blocks and springs. They reason about the sign of the net external work done on each system, as well as the sign of the kinetic, potential, and total energies of each system. This motivates the idea of conservation of energy, which is introduced at the end of the section.

Section II: Comparing changes in energy

Students are shown a similar experiment. They use the idea of conservation of energy to rank the change in total energy for the three systems. A similar ranking is then done for the change in kinetic energy and change in potential energy.

Section III: Supplement

Students consider a system of two blocks being pushed from the left (Case X) and from the right (Case Y). In each case, they apply Newton’s 2nd law and the work-energy relationship.

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Students should have been previously introduced to the ideas of work from a single force, kinetic energy, spring potential energy, and the idea of total energy as a sum of different types of energy.

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