Rob was supposed to spend his two-week school work experience at his local auto-

Question

Rob was supposed to spend his two-week school work experience at his local auto-repair shop. Unfortunately, his time on the job only lasted two days. On day two, Rob was asked to get the 1 litre air tool oil which was sitting on the work bench, however, as his hands were full of grease, instead of wiping them on a nearby rag, Rob decided to elbow the 34- full can of oil across the work bench. This was a very bad idea because he pushed the oil can with such force that it slid 473 mm across the bench before tipping over and beginning to spill its contents. Rob rushed to pick up the can, but in his haste, he tripped over the newspapers which had been placed under the two left legs of the work bench – the newspapers were there to soak up the motor oil which Rob had spilled the previous day – and fell flat on the floor bumping the legs of the work bench causing it to tip over and fall on top of the mechanic on the other side. a) Taking the density of the air tool oil to be 865 kg/m3 and the mass of the empty can to be 0.726 kg, what was the total weight of the can before the spill? b) If the newspapers under the left legs of the work bench propped up the work bench to a slope of 9.4-degrees with the flat ground, what was the applied force on the can of air tool oil as it was moving across the bench prior to it stopping and tipping over? Take the coefficient of kinetic friction for steel on steel to be k = 0.60. c) Neglecting the energy required to tip over the can of air tool oil and assuming no energy losses in the form of heat, how much work did Rob perform in moving the can of air tool oil? d) Is this work path-dependent? BSC107C_Assessment3_PaperB_v1.docx Bachelor of Science (Engineering) 4 e) If the heat generated by moving the can of air tool oil across the work bench had not been negligible in this case, it may have contributed to a safety hazard. Discuss the differences between heat and work in terms of molecular motion and internal energy. f) The air tool oil is chemically identified as: petroleum distillates, hydrotreated heavy naphthenic. Discuss this product in detail. Focus your discussion on the type of elements and compounds in this product, the predominant type of chemical bonds, and other relevant chemical information. Include chemical formulae, sketches, and/or other relevant information pertaining to the main constituents of this product to support your answer.

Explanation / Answer

Goddard's work as both theorist and engineer anticipated many of the developments that were to make spaceflight possible.[3] He has been called the man who ushered in the Space Age.[4]:xiii Two of Goddard's 214 patented inventions—a multi-stage rocket (1914), and a liquid-fuel rocket (1914)—were important milestones toward spaceflight.[5] His 1919 monograph A Method of Reaching Extreme Altitudes is considered one of the classic texts of 20th-century rocket science.[6][7] Goddard successfully applied three-axis control, gyroscopes and steerable thrust to rockets to effectively control their flight.

Although his work in the field was revolutionary, Goddard received very little public support for his research and development work. The press sometimes ridiculed his theories of spaceflight. As a result, he became protective of his privacy and his work. Years after his death, at the dawn of the Space Age, he came to be recognized as one of the founding fathers of modern rocketry, along with Robert Esnault-Pelterie, Konstantin Tsiolkovsky, and Hermann Oberth.[8][9][10][11][12] He not only recognized the potential of rockets for atmospheric research, ballistic missiles and space travel but was the first to scientifically study, design and construct the rockets needed to implement those ideas.[13]NASA's Goddard Space Flight Center was named in Goddard's honor in 1959.

Early life and inspirationEdit

Goddard was born in Worcester, Massachusetts, to Nahum Danford Goddard (1859–1928), a farmer, and Fannie Louise Hoyt (1864–1920). Robert was their only child to survive; a younger son, Richard Henry, was born with a spinal deformity and died before his first birthday.[14]:16 Goddard's family had roots in New England dating to the late 1600s. Shortly after his birth the family moved to Boston. With a curiosity about nature, he studied the heavens using a telescope from his father and observed the birds flying. Essentially a country boy, he loved the outdoors and hiking with his father on trips to Worcester and became an excellent marksman with a rifle.[15]:63,64 In 1898 his mother contracted tuberculosis and they moved back to Worcester for the clear air. On Sundays the family attended the Episcopal church, and Robert sang in the choir.[14]:16

Childhood experimentEdit

With the electrification of American cities in the 1880s, the young Goddard became interested in science—specifically, engineering and technology. When his father showed him how to generate static electricity on the family's carpet, the five-year-old's imagination was sparked. Robert experimented, believing he could jump higher if the zinc from a battery could be charged by scuffing his feet on the gravel walk. But, holding the zinc, he could jump no higher than usual.[14]:15[16]Goddard halted the experiments after a warning from his mother that if he succeeded, he could "go sailing away and might not be able to come back."[17]:9 He experimented with chemicals and created a cloud of smoke and an explosion in the house.[15]:64 Goddard's father further encouraged Robert's scientific interest by providing him with a telescope, a microscope, and a subscription to Scientific American.[17]:10 Robert developed a fascination with flight, first with kites and then with balloons. He became a thorough diarist and documenter of his work—a skill that would greatly benefit his later career. These interests merged at age 16, when Goddard attempted to construct a balloon out of aluminum, shaping the raw metal in his home workshop, and filling it with hydrogen. After nearly five weeks of methodical, documented efforts, he finally abandoned the project, remarking, "... balloon will not go up.... Aluminum is too heavy. Failior [sic] crowns enterprise." However, the lesson of this failure did not restrain Goddard's growing determination and confidence in his work.[14]:21

Cherry tree dreamEdit

He became interested in space when he read H. G. Wells' science fiction classic The War of the Worlds at 16 years old.[18] His dedication to pursuing space flight became fixed on October 19, 1899. The 17-year-old Goddard climbed a cherry tree to cut off dead limbs. He was transfixed by the sky, and his imagination grew. He later wrote:

On this day I climbed a tall cherry tree at the back of the barn … and as I looked toward the fields at the east, I imagined how wonderful it would be to make some device which had even the possibility of ascending to Mars, and how it would look on a small scale, if sent up from the meadow at my feet. I have several photographs of the tree, taken since, with the little ladder I made to climb it, leaning against it.

It seemed to me then that a weight whirling around a horizontal shaft, moving more rapidly above than below, could furnish lift by virtue of the greater centrifugal force at the top of the path.

I was a different boy when I descended the tree from when I ascended. Existence at last seemed very purposive.

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