environmental science, Assignments of Environmental Science

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Passage VI The energy, as measured in joules (J), that an object has by virtue of its position with respect to nearby masses is called gravitational potential energy (GPE), while energy of motion is called kinetic energy (KE). An object falling toward the earth has both gravitational potential energy and kinetic energy. An object's total mechanical energy (TME) is the sum of GPE and KE. Objects in motion lose total mechanical energy because of friction. Experiment 1 A steel marble weighing 1 kilogram (kg) was placed on a track and allowed to roll as shown in Figure 4. A series of photogates (timing devices useful for measuring events which happen faster than can be timed by hand) were used to determine the speed of the marble at various positions on the track. The speed of the marble was used to calculate its kinetic energy. The results are given in Table 7. 1.25 m =-------------------- - eH - J << Photogate 1.00 m a a ah a J <—\ Photogate 0.75 m ---------f~ -----\--------- J <— Photogate 0.50 m Se ee eee se Ne ee ee 7 << Photogate 0.00 m a Photogate H Table 7 Figure 4 Height GPE KE (m) 0) 0) TME (J) A 1.25 12.25 0.0 12.25 B 0.75 7.35 48 12.15 C 0.50 4.90 72 12.10 D 0.75 7.35 4.5 11.85 i a E 1.00 9.80 19 11.70 s F 0.75 7.35 43 11.65 G 0.50 4.90 7.2 12.10 CxMprRIDGE H 0.00 0.00 11.5 11.50 Tirsorsse sen 33. 34. In Experiment 1, if point E of the track were raised to the same height as point A, what would be the probable result? A. The marble would arrive at point E with the same total mechanical energy as at point A. B. The marble would arrive at point E with greater total mechanical energy than at point A. C. The marble would arrive at point E with less total mechanical energy than at point A. D. The marble would exhaust its kinetic energy before reaching point E. In Experiment 1, gravitational potential energy of the marble depends on the: F. height of the marble on the track at any given point. G. speed of the marble at any given point along the track. H. horizontal distance between the points along the track. J. physical composition of the marble used. 35. In Experiment 1, total mechanical energy of the system is lost to air resistance, friction between the marble and the surface of the track, and other factors. If Experiment 1 had been conducted under ideal conditions with no such factors, then: A. gravitational potential energy at point A would equal kinetic energy at point E. B. gravitational potential energy at point A would equal kinetic energy at point H. C. gravitational potential energy at point A would equal gravitational potential energy at point H. D. kinetic energy at point C would equal kinetic energy at point H. = i CAMBRIDGE TEnecationat Seavie