Exam 2: Tonight 8:20-10:10pm

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1 xa : Toniht 8:0-0:0p oo ssinents: ast Nae oo - NN 7 F-K TU 007 -O 064 P-S CB C0 T-Z CCC 00 Breakdown o the 0 Probles aterial # o Probles Chapter 6 Chapter 7 4 Chapter 8 5 Chapter 9 6 Chapter 0 Crib Sheet: Calculator: You a brin a sinle hand written orula sheet on 8½ x inch paper (both sides). You should brin a calculator (an tpe). Scratch Paper: e will provide scratch paper.. Field /08/ Universit o Florida PHY 05 Pae

2 xa Fall 00: Proble 9 projectile is ired straiht upward ro arth's surace with a speed that is hal the escape speed. is the radius o arth, the hihest altitude reached, easured ro the surace o the arth, is: nswer: / % iht: 9% scape Speed i v esc v esc G 0 G G r G i ( vesc / ) G r i G G ( vesc / ) ( 4 ) r 4 h r. Field /08/ Universit o Florida PHY 05 Pae

3 Final xa Sprin 0: Proble unior disk with ass, radius 0.50, and oent o inertia / rolls without slippin alon the loor at revolutions per second when it encounters a lon rap anled upwards at 45 o with respect to the horizontal. How hih above its oriinal level will the center o the disk et (in eters)? nswer:.0 % iht: 9% H v ω ( H ) i v ω ω π ω ω v v π (0.5) 9.8 / s v ω ω π ( / s) H θ 45 ο x-axis.0. Field /08/ Universit o Florida PHY 05 Pae

4 xa Sprin 0: Proble 9 odern sculpture has a lare horizontal sprin, that is attached to a 60-k piece o unior etal at its end and holds the etal at rest at an anle o θ 60 above the horizontal direction as shown in the iure. The other end o the etal is weded into a corner and is ree to rotate. the sprin is stretched 0. what is the sprin constant k (in N/)? nswer: 849 % iht: % sin( ± B) sin cos B ± cos sin B k xsin θ cosθ 0 k x θ (60k)(9.8 / s ) o k cotθ cot(60 ) 849N / x (0.). Field /08/ Universit o Florida PHY 05 Pae 4

5 xa Fall 0: Proble 7 cloth tape is wound around the outside o a nonunior solid clinder (ass, radius ) and astened to the ceilin as shown in the iure. The clinder is held with the tape vertical and then release ro rest. the acceleration o the center-o-ass o the clinder is /5, what is its oent o inertia about its setr axis? nswer: % iht: 48% F T a F T ( a ) τ FT α a F T -axis F a a T 5 a 5. Field /08/ Universit o Florida PHY 05 Pae 5

6 xa Fall 00: Proble unior plank is 6 lon and weihs 80 N. t is balanced on a sawhorse at its center. n additional 60 N weiht is now placed on the let end o the plank. To keep the plank balanced, the sawhorse ust be oved what distance to the let? nswer: % iht: 48% 80N 60N 6 d d 60N d 80N 60N 0 d /. Field /08/ Universit o Florida PHY 05 Pae 6

7 . Field /08/ Universit o Florida xa Fall 0: Proble 0 Two pendulu bobs have asses k and B k and equal lenths as shown in the iure. Bob is initiall held horizontall while bob B hans verticall at rest. Bob is released and collides with bob B. The two asses then stick toether and swin upward to the riht to a axiu anle θ. hat is the axiu swin anle θ? nswer: 50. o % iht: % v i ( B ) V ( B ) h V h B v pi v p ( B ) V h cosθ o θ 50. h ( cosθ ) B B Beore 90 o PHY 05 Pae 7 V B B 90 o B ter θ ter θ cosθ h

8 Final xa Fall 00: Proble block o ass is attached to a cord that is wrapped around the ri o a lwheel o radius and hans verticall, as shown. The rotational inertia o the lwheel is /. when the block is released and the cord unwinds the acceleration o the block is equal to /, what is the ass o the block? nswer: / % iht: 5% s v a θ ω α. Field /08/ Universit o Florida F T a τ α F T a a a a FT α a -axis PHY 05 Pae 8 F T

9 . Field /08/ Universit o Florida xa Fall 00: Proble 6 ouse o ass /6 lies on the ri o a solid unior disk o ass that can rotate reel about its center like a err-o-round. nitiall the ouse and disk rotate toether with an anular velocit o ω. the ouse walks to a new position that is at the center o the disk what is the new anular velocit o the ouse-disk sste? nswer: 4ω/ % iht: 58% i i i disk ω ( )ω ω ( )ω disk new disk nitial P 4 ω ω ω ω ω new disk ω i Note that ener is not conserved in this proble! disk Final P PHY 05 Pae 9 ω i i i 9 ω

10 . Field /08/ Universit o Florida xa Fall 00: Proble 0 Suppose that ou release a sall ro rest at a depth o 9. below the surace in a pool o (with densit ) near the surace o the arth. the densit o the is / the densit o, how lon does it take the to reach the surace? nswer: s % iht: 5% d t a t d a d t F buoanc -axis d PHY 05 Pae 0 V V a a V ( ) a (9.) 4s (9.8 / s ) s

11 Final xa Fall 00: Proble block o has a ass o 4 k and densit o 600 k/. t is loaded on top with lead (densit,400 k/ ) so that the block o will loat in with 90% o its volue subered. hat is the ass o the lead i the densit is,000 k/? nswer: k % iht: 46% V sub lead. Field /08/ Universit o Florida ( ) ( ) a 0 V 0.9(,000 k / 600k / lead V sub ) V V sub lead k lead F buoanc -axis ( lead ) PHY 05 Pae

12 xa Fall 00: Proble 9 n object hans ro a sprin balance. hen subered in the object weihs one-hal what it weihs in air. when subered in an unknown liquid with densit X the object weihs three-ourths what it weihs in air, what is the densit o the unknown liquid? nswer: % iht: 4% 0 ir F sprin 0 iquid F sprin liquid F buoanc 0 liquid 0 liquid 0 X liquid liquid V X V 0 liquid V X 0 0 X Field /08/ Universit o Florida PHY 05 Pae

SECTION A Torque and Statics

SECTION A Torque and Statics AP Physics C Multiple Choice Practice Rotation SECTON A Torque and Statics 1. A square piece o plywood on a horizontal tabletop is subjected to the two horizontal orces shown above. Where should a third