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2010s_4

# 2010s_4 - I Physics 2101 Exam#4 Spring 2010 Name EY...

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Unformatted text preview: I) Physics 2101, Exam #4, Spring 2010 April 28, 2010 Name: EY Section: (Circle one) 1 (Rupnik, MWF 8:48 AM) 5 (3:11, TTh 12:10 PM) 2 (Illuarrik1 MWF 10:40 AM) 6 (Gonzalez, T’I‘h 4:40 PM) 3 (Zheng, MVVF 12:40 PM) 7 (Sprunger, TTh 1:40 PM) 4 (Plummer, TTh 9:10AM) 9 Please be sure to write (print) your name and circle your section above. - Please turn OFF your cell phone and MIPB player! 0 Feel free to detach, use, and keep the formula sheet. No other reference material is allowed during the exam. - You may use either scientiﬁc or graphing calculator a GOOD LUCK! SHOW WORK on all problems that are NOT multiple choice l. (10 pts) Three spherical objects with the same mass m kg are separated by equal distances L by forming a triangular structure. How much work is done by you to set the masses in this conﬁguration, bringing them from an inﬁnite distance? ~er (a) +G‘m2 / L 0 e. 2 ... _. _, . .—.-._- ﬂ (b) —Gm/L WWPA’M- ﬁg jag G L (c) +3Gm2/L —3Gm2 / L 2. (10 pts) A satellite is launched in a circular Synchronous orbit around the earth. Neglecting all possible resistance from atmosphere, you conclude based on your knowl- edge of gravity that... (a) The height of the orbit depends on the mass of the satellite. (a) The height of the orbit‘ 1s independent of the mass of the satellite. (c) The height of the orbit depends on the mass and size of the satellite. (d) None of above is correct. 3. _f-F HE. ”F’K'L?’ ( 15 pts) A cubical block of wood, 10.0 cm on a side, ﬂoats “36%! at the interface between 011 on top and water below, with its lower surface 3.50 cm below the interface (see the cross section view in the ﬁgure). The density of the oil is 790 kg/m3. €95 740 1,75%;- h :3 gm ,. - 3 .._.. o f' 7 W, 1000 Alf/VIA L s 10 MfQ'M ~21- L (a) (5 pts) What is the gauge pressure at the upper face of the block? ,Fwﬂ :-: fpﬂfcﬁ ﬂea. 3(740 %}[‘7£%3><35m61é9 W =7- 7an7 P61, (b) (5 pts) What is the gauge pressure of the lower face of the block? (FW: \$8er .+ fw‘jxh ;(’770%ﬁ»€%§)@lim 9i” @0530 igﬁee 32;) (st7 M61): HE: (C) (5 pts) What is the mass of the block? Hint: use parts (a) and (b) to ﬁnd your answer. ,— )ﬁeezo % w“?: E I: ﬁery—pm is? 5 L7ﬁ¢btf ﬁx?) :0 \$7 W MIN 3 4. (10 pts) In the ﬁgure, a spring with spring constant it is . .3331“ . . . _ immense] .1 between a, I'lgld beam and the output piston of a hydraulic Staring“ lever. An empty container with negligible mass sits on “g the input piston. The input piston has area A and the output piston has area 15A. Initially the spring is at its rest length. Then, a mass M of sand is slowly poured into the container. A 1 9—15: (a) (5 pt) What is the change of pressure on the output piston, due to the send poured into the container? .Mg/A Afr; : ”21\$; iii. Mg/(15A) A iv. Mgr/(7.514) VFW www‘ Afizﬁ'lps— M __ _ .5 rem? 3?? {figs/t 5‘ e (b) (5 pt) The spring is compressed by a distance iii. Rig/(15k) iv. Airy/(7.519) 5. (15 pts) In the ﬁgure below, two identical springs of spring constant it = 2.5 N / cm are attached to a block of mass m— — 0. 20 kg. The block is set into motion by displacing the block 3.0 cm to the right of equilibrium, and letting it go from rest. Lﬂaseq , F r &52,§é%ﬂ ‘M *250’ . ,7 _.___ 1 ‘4‘” 4:»: X344 7'sz 5 0. 0?, (A?) 1.111.”, . _ .... .-. ..., ' _ 'WL :; 01 20 £3 «5‘- (a) ( pts) What is the period T of the oscillatory motion? ZT= AX Cd" 23% “high—E), AXE—EQKAX _; 4?; «.- 12; +132: 2 is. W- (b) (5 pts) What is the block’s maximum velocity? :__—' Q); gr: Life-5' I. V; A“ XW‘T' (3%; M MM“; % (c ) (5 pts) At what time wili the block go for the ﬁrst time through the equilibrium position with negative velocity? 25 w T/Z t = 3274 / 6. (15 pts) A sinusoidal wave moving along a string with mass m. = 1.25 kg and length 100.01n is shown twice below, as crest A travels in the positive direction of an 3: axis by distance d = 1.0 cm in 50.0 ms. The tick marks along the axis are separated by 2.0 cm. The snapshot shown with a solid line is taken at t = O, the one with a dashed line is taken at a later time. The wave equation is of the form y(m, t) 1 gm sinUcw — wt). (b) (5 pt) At t I: 0, which of the following is the velocity vector of the particle in the string at a: m 0? P . . ﬁmwx? 44a awe QMW idea aye/ow ear Maze M1:oavmcﬂeﬂmc€ T o w» _ (c) (5 pt) What is tension in the string? esz—i’; :9 i”:«tt7c:@¢§)z(orm2§%); 91104“ “id—u... ft: gxqu—M . {10 pts) You want to design an engine with a brass piston to slide inside a steel cylinder. This engine should Operate between 20°C and 150°C. The linear expansion coefﬁcients for brass and steel are 0133 = 2.0 x 10‘5/°C and 05531 = 1.2 x 10—5/°C. Assume that the coefﬁcients of expansion are constant over this temperature range. (a) (5 pt) If the piston just ﬁt inside the chamber of the cylinder at 20°C, will the engine be able to run at higher temperature? a , _ s. M i 9. saw We We the We 61:0" % 6th M mi {emu MWW iii. It depends on the size of the piston. 9% W (b) (5 pt) If the cylindrical piston is 25.0 cm in diameter at 20°C, What should be the minimum inner diameter of the steel cylinder at that temperature so that the engine will operate at 150°C? ®> 25.00111 ﬁeeg 6%?)de ,W} (9-0 A3“ £194 7% i1.25.0cm be 2 _ d, 510% Oh“? i. 1 iii. < 25.0 cm 8. (15 pts) A block of ice with a, mess of 2 kg at initial temperature of m20°C is mixed with with 3kg of water at room temperature, 20°C. The latent heat of fusion of ice is L f = 333 kJ/kg.’ The speciﬁc heat is cm ,2 2220 J / (kg°C) for ice and cw m 4187 J/(kg°C) for water. (a) (3 pts) How much heat is needed to warm up this piece of ice to 0°C? A AAA 42%) Maia-AAAXAAMW} A (b) (3 pts) How much heat is needed to melt all the ice? Qz=wg Lg 3(2131/3336390 Wag): £546 06 6 ‘3. HF—du- ? QmZQﬁ'QL—T‘7V4QUO}. ' (c) (3 pts) How much heat does it need te be extracted from the water if it were to cool to 0°C? 'W' 'w 14 3% WW# ((1) (3 pts) What is the comp All frozen ice All liquid water ' mixture of ice and water (6) (3 pt) What is the ﬁnal temperature Tf of the mixture? Tf < 0°C m 0°C < T; < 20°C T]: > 20°C ...
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2010s_4 - I Physics 2101 Exam#4 Spring 2010 Name EY...

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