Sample Exam 3A and solution

# Sample Exam 3A and solution - Print Name: ’ \$OLWOI~J ~ 5...

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Unformatted text preview: Print Name: ’ \$OLWOI~J ~ 5 - V Department of Mechanical Engineering ea " " 24-101 Fundamentals of Mechanical Engineering Fall Semester, 2006. Exam #3 This exam is closed book and notes. T 0 receive partial or full credit, organize and explain your work ' and draw clear diagrams. Work on the supplied paper only. If the units for an answer are speciﬁed, give your answer in those units only. Total 100 ts (a) The pressure at the bottom of 12 ft deep sWimming pool is how much greater than on the surface? I 1. Short answers (15) A? = (2%“ 1 (m4 iggx‘szz gixizgk‘) — quicmo _\~3_ (micro 7‘3; -— Slob \$427. €\Z\ I (b) A bullet of diameter 0.3 in leaVes the barrel of a riﬂe at 2400 ft/s. Calculate its Reynolds number. cl = 0.025 gb \U‘L COL/155M gawk: (zrszmeﬁ eagslxcéXzi-ioo §b{s_)(o\ozs £52 125 ' 3‘1; ’00"? sealers-53 . 5' 3 \$08 3‘ ‘0 (c) The Viscosity of an oil lubricant is 240 CR Express that quantity in the USCS. l'P (5A Mﬁﬁ H , /U\.'- 204? u C9354 M’s (oaqﬁwemszu \e" ﬁwtoaoriﬁ if) = 5‘0‘2"‘63 4: 5 5012 3L {0’3 slugs/(ft-s) 2. (a) Label the indicated components of the engine using conventional engineering terminology. (+1" -point for each correct answer, 0 oints for no answer, -1 'oint for incorrect answer .- 10 ' . 1n: “ w , q , . , . Q; “a a < \Nme’c Vabe ’?.\\'\ ' I w\$v% ‘ 'v0\\)'e amifdwg (DIM \sl-CM Cmvoi shag (DA 9“”? CWW . “EVE 4 (b) Explain the ur-‘so engin' cycl rising drawins and words. (10) R%S ZCOO - 2103 3. The work piece hOIder in a milling machine is pushed by a lead' screw at 15 cm/s over two guideways. Each guideway is 40 cm long and 8 cm wide, and lubricated with 25.6 pm of SAE 30 oil. Neglecting any friction in: the leadscrew itself, how much. power is necessary to move the workpiece holder at that speed? How much power is needed to move the workpiece holder twice as fast? (20) \$‘cfecu- Qoress \Uk ox\ \oxaex - __ E exams t (O‘ZQN'Q zlsttosuo'b W1 1D: (qq‘szOt\5 WIS). " ill-M03 W Wee Sfeitk) ’C (3 have as lavaeJ cmd We power \5 Powerat 15 cm/s= Hubs W Power at 30 cm/s = 53‘ g W 4. The aluminum bar AB is attached to its support by a round pin of diameter d = 16 mm and yield strength 150 MPa. The bar has thickness t = 15 mm, width b =_ 40 mm, and is made from a material with a yield strength of 250 MPa. In order for the factor of safety of the pin/bar system to be atleast two, what is the maximum allowable load P? (20) EC»?- - 5» ' ' - WCAVLD' ‘ 2“ ‘~ 125 M’Pq (P = T A ‘ (lZleOb—L—j— (6\O\Sw>(O|O‘-/M = 45' g/U 0"\\OUD OA‘CLD ‘ M2, ‘1? ‘5 CLwa \$‘necmj go \fzi: _ VSOMPOL __ I z: 653 _ a\\og,o ? - 55 WQ \/cg\\m = ZCAW A 0C T3on = ’Z task“) A TDosxcw= 2(316MOQ—u’i (E-Xoow m}? = «508 2+) Maximum allowable load = [5. l KN rémaécevx‘: mks, ’p: (\xzhabsgo ﬂ): (we 5. The experimental solar powered car transfers 1.2 hp of power to its wheels for propulsion purposes. (The photovoltaic solar cell panels on the car’s roof develop substantially more power, but after taking into account the efﬁciency of the solar cells, power electronics, and electric motors, only 1.2 hp is available for propulsion.) The vehicle has a frontal area of 9.5 ft2 and a 0.2 coefﬁcient of drag. The only signiﬁcant resistance is air drag, so you can neglect rolling resistance between the tires and the road, and all sources of friction. Calculate the vehicle’s speed and the air drag force. Recall that 1 mi = 5280 ft. (25) ' mg ems www- . (13/ “A CD \v\ “93 —'\$ = 'Z.Z\‘-l 1410 03' 2‘2Nmo‘3q-3: (0(90 4% 0" (0(0.<3\ 5; %%2 VB: (zamxndéxcocsafgy‘ ‘ C1668 \5 Speed = [45‘ g; rni/hr Drag force = Cl 56? 1b ...
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## This homework help was uploaded on 04/09/2008 for the course MECHE 24-101 taught by Professor Leduc during the Fall '07 term at Carnegie Mellon.

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Sample Exam 3A and solution - Print Name: ’ \$OLWOI~J ~ 5...

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