CU 2008 fa exam3 key

CU 2008 fa exam3 key - at the bottom “3‘s and 6<°" “2:6 War the object slides the length{of the hill If the ‘2'0f7 1 A m = 5 kg

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Unformatted text preview: , at the bottom? “3‘s and: 6 <° " “2:6 War. , the object slides the length {of the hill. If the ‘2'0f7 1. A m = 5 kg object, starting at ., top of the hill, slides without friction the h = 12 m hill shown. What is its speed A) 4.9 m/s 2 D) 4.5 m/s E) 10im/s C) 12 m/s RE... "i' P _‘ k5; *‘_ 0 *Msk - V; who , :25“ _, 2. Suppose, for this same hill, there is v h friction and that 200 J is lost to heat when object starts at the bottom of the hill, what Maia‘Z—JE3:{TJIF flag—S: is the minimum initial speed the object _L M02- : Msk + Ema”, Lid—k 2. ' €T~afi us must be given so that it makes it from the a 5.6 3‘; #2410 ' ' ' 9 to bottom ofthe hill all the way to the top. &(¢) “‘3. 6152.00 :1 g 3‘0 F“... A) 15.5'm/s B) 12.3 m/s A C) 10.0 m/s (D) 17.9 m/s) E) 6 m/s ‘- ‘73 "14 3. The angular speed of the Earth‘in its orbit'around the sun is' i oAI‘h-sflw ; » :L. can. , A) 7.3 ><‘10’5 rad/s B) 3.6 x 10-5 rad/s C) 2.0 x 10'7 rad/ O? 31%} A 2. -46 P .1 O“ D) 2.7x10+5rad/s 2 E)l.9X10+7rad/s e “ "0, =2qu mi 4. A 2000 kg SUV traveling at 15 m/s strikes an 80 kg cyclist traveling in the same direction at 10 m/s. cyclist and the SUV stick together. What is their final speed? Comma-‘5“ ‘A Minus . m. .. m, g u... “JV (awn-'4: soda) 52°50; 2,5 A) 15.0 m/s ' B) m/s C) 12.2 m/s D) 13.5 m/s h‘K‘k ' dam}; 5. In the previous problem, how much kinetic energy is lost in the collision ? A)01» ,B)30,000]" (b70001 D)800J, ‘L Mtv\L~ ‘33“). F242 k E -‘- them‘taY e: 2'22 :00 ~ v. 3 of 7 6. A softball of mass m = €9.20 kg is heading to the left toward the batter at 20 Ill/8.! It is hit by the bat and . 20 “1/8 heads fight at 40 m/sv. If the; collision with the bat lasts 0.02 5, what is the magnitu e of the force exerted by 40 mm 4 eds-w = mam—(«.3 ‘ thebatontheball? V (cm) gamma, cgqh‘w: “QM @ B)300!N C)200N D)6N E)2N 0,02- i 7 .1 A rocket works by mixihg a fuel and liquid oxygen, burning the fuel in the ' combustion chamber and shooting the high velocity gas out of the nozzle. [ The rocket works because (pick the best - ' answer): _ A) the expanding gas pushes on the air , B) the gas carries momentum backwards us ; s on the rocket x" E) A and B and C . A .2. m5, 1m...“ «Jet wok w I o s (‘9 h i “fies . “31‘” 24 a; P4 gc—l C a...» UNA Tau -“M-hxwin cunt w swtfiut‘wmg 8. An earth-orbiting satellite in the shape of a rod of “9" L l , A uniform length L, is rotating about an axis { perpendicular to its length through its center with an ‘ : initial angular speed of 10 revolutions per minute. ' ' g The satellite then extends tp a total length of 3L. What is the final angular speed of the satellite? (:::0 E I 1.11 rev/mi B) 30 rev/min C) 5.0 rev/min E ' D) . rev min E) 3.33 15gvlmi w I a l l Cogswd nu 494$“qu \M*gm '1‘ \U\ = $3.63, > leguo XLcEfLM(3L a Mw 194L912") a. _ Wax w‘ c to: M.- .\.1\ rec/“‘W 1 1/4/2008 4of7 The next 3 questions refer to this situation: A ball is thrown upwards so that it just barely goes over the edge of an inclined plane 20 m high, as shown in the diagram. It then rolls without sliding down the inclined plane. (Assume that air resistance and other heat-generating processes are negligible.) Cow“; “I‘Iér‘fg 9. The initial speed of the ball, as it is thrown upwards, is m:— *‘ 5' L,“ r u+0=~vfl+¢ A14m/ B10m/ C18m/ D15m/ E20m/ ‘13”? ) ) s ) s ) s ) s =mkls 10. The final speed of the rolling ball when it reaches the bottom of the inclined plane is its initial speed when first thrown upwards. , lk . JD . SN 1 01.0. w‘ 8‘ ' A) greater than B) equal to ’ C) less than ‘0‘, “55%. “J “a. M 5.0.0. wok";— ‘hn. lea. V 11. The final total kinetic energy of the ball (rotational plus translational KE) is its initial total kinetic energy when first thrown upwards. A) greater than ‘B) equal to > C) less than an etude .6 Gm, tJ'GLcay wjab unsung. 11/4/2008 ’ _ 50f7 12. Consider the seesaw shown in the diagram. An 80 kg person sits 5m from the fulCrum. If the seesaw is to person from the fulcrum? I B)3.0m 7~=o be balanced, what must be the distance of a 200 kg 80 kg E) 0.85 m 0mg =DM c) 4.0m ‘ D) 1.5m 100 & 4:036 13. What is the upward force exerted by the fulcrum on the seesaw? A) 160N B) 320 2F=a N C)800N D)2000N(E)2800N% \Cgo) ?A VM‘ + :2 tb‘fo . cm» 8 M6318 N 14. A hoop and a solid cylinder, each with the same radius R, roll down the same inclined plane, starting from rest. Which statement is true? A) The hoop reaches the n C) They reach the bottom at the same time regardless of the masses. D) The cylinder will win if the masses are equal, but the hoop will win if its mass is significantly greater than the cylinder. . 1 1/4/2008 60f? 15. A spring of negligible mass is compressed between two masses on a frictionless table with sloping ramps at each end. (Note: the masses are not attached to the spring in an initially at rest, are release M2. Select the appropriate than), or E (Equal to). M1 way, and so will fly apart after release.) The masses, simultaneously. The mass M1 is greater than that of , M2 , 1) The magnitude of Ml's mo entum is . that of M2 before d just after loss 02.0 contact with the spring. “a spring. 3) The kinetic energy of M Contact with the spring. \{E -'—‘ )LMO“ 4) The final height up the ramp reached by ‘6 that L. o), ken” V 1G 1 M\ V\ a H:- thekinetic W L 64-43.. "" “Mk 2) The speed of M1 is the Kid of M2 once the both lose contact with the 1 is = new M1 is)? Rant Thecorrect' - e: A) LLEE C) EGGG D) GGGE E) ELLE 16. A 1.0 kg bicycle wheel of radius 0.35 m is attached to a stand which allows it to rotate freely. It rotates with an angular speed of 20 rad/s. How much force must be applied to the rim of the wheel to stop the wheel in 4 s? w B)O.875N‘ C)3.50N D)7.F0[(‘)’N E)4.15N “5°16- we) (x: ~Wo a f ’- ~ 1 1/4/2008 ~20 L; ‘- Q Iot {to . . . ‘ .F’ 1‘7 305' 17. A solid disk of radlus R = 3.00 m, mass M = 3.5 kg, is spinning at a constant rate of 50 revolutions per minute about an axis through its center. What is the magnitude of the angular acceleration oz of the wheel in rad/s2 ? A) 3.14 rad/32 B) 5.24 rad/s2 C) 9.15 rad/$2 @ E) None ofthese. =0 symbol for each statement: G (Greater than), L (Less H LMSW V. 4 \IL 2 once they both 10s mi“ C" 6 height reache by M . Cc lens a. “Queue. M PM" 5‘5” ‘ N 7of7 18. A person is initially standing on the rim of a merry—go—round which is spinning at a constant rate of 6, rpm (revolutions per minute). There is a motor on the ‘ merry—go—round which keeps the rotation rate constant at all times; The person then moves inward and stands near the ' center of the merry-go—round. What happened to the person's 0) magnitude of her (linear) acceleration a as a result of / changing positions from the rim to near the center. speed V, the magnitude of the angular velocity (0, and the A) v increased, 0) stayed constant, a increased B) v increased, (0 increased, a stayed constant A - x U 9. r w s a V W C) v decreased, wincreased, a decreased at ,3, v2. 1:, IF 5 D) v increased, to stayed constant, a stayed constant c x :19. w decreased, 0) stayed constant, a decreased OUR (0" 50 r ck . Awté ‘1 W 19. Two 1 kg masses are traveling toward one another as shown and collide. @=37°andCD=53°. ‘ , , _ V V V she-t- “a.” S" ) V1: g. The y-component of the total final momentum is (select closest answer): A) +500 kg m/s B) -225 kg m/s D) —600 kg m/s E) +400 kg 111/5 20. True (A) 0 False (B): Isaac Newton won the Tour de France in 1690. sue. , K ‘M , * ' 113008 $5.“ch ...
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CU 2008 fa exam3 key - at the bottom “3‘s and 6<°" “2:6 War the object slides the length{of the hill If the ‘2'0f7 1 A m = 5 kg

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