1 .		A weight lifter picks up a barbell and lifts it chest high holds it for 5 minutes puts it down. Rank the amounts of work W the weight lifter performs during these three operations. Label the quantities as W1, W2, and W3. Justify your ranking order.   To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
2 .		Estimate the amount of work the engine performed on a 1200 kg car as it accelerated at 1.2 m/s2 over a 150 meter distance.   To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
3 .		A real world roller-coaster released at point A and coasting without external power would traverse a track somewhat like the figure above. Friction is not negligible in the real world. If we call the potential energy at point A relative to the ground Uo what can you say about the potential and kinetic energies UB, UB at point B and the potential and kinetic energies UC, UC at point C.   To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
4 .		A gallon of gasoline contains about 1.3 x 108 joules of energy. A 2000-kg car traveling at 20 m/s skids to a stop. Estimate how much gasoline it will take to bring the car back to the original speed. To complicate matters further, consider the fact that only about 15% of the energy extracted from gasoline actually propels the car. The rest gets exhausted as heat and unburnt fuel.   To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.