exam-1A-K10-soln

exam-1A-K10-soln - 1 A block of mass 5.0 kg is suspended by...

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Unformatted text preview: 1. A block of mass 5.0 kg is suspended by a rope from the ceiling of an elevator. The elevator (and the block) is accelerating downward at 3.0 mfsz. The tension force of the rope on the block is: A) UN """ "Kill B) 15N \$11 an%_’r:mcr CC) 353 “A D) 5N an I __ f: {mtg-00; \! .4 _ ’ L a: sewn? " Sﬁlo 3) WV; iE) none of these 2. A ﬁreﬁghter weighing 800 N slides down the 6.0 In pole in the ﬁrehouse. He grips the pole in a way that creates a frictional force of 740 N, which is constant as he slides down the pole. Approximately what is his speed when he reaches the bottom? (Assume his initial downward speed was zero.) A) 1.0m/s B) 2.0m/s an : (i00ﬂ74eyxtzé‘0/V “m: £92; . IO ? I .. . D) ‘. III/S w z AZ .— E) noneofthese ___ (goxsvj :- 36‘03’ oﬂzg Wt .— —- 3GB 1 .. * 31;va - 3603' \1 #ffw/S - SEW/5 Z + 5‘ and neither 2 nor 5' vanish (i.e., neither is zero), then: 3- If|Z+E A) Z and B are parallel andW B) A and B are parallel and a opposite directions C) the angle between H and E is 45° D) the angle between 21 and E is 60° \‘3\ E) Z is perpendicular to E W 1'2 {gt 4. A particle moves 5.0 m in the positive x-direction while being acted upon by a constant force 1—5 a (4 N)? + (2 N)}'2 — (4 N)k. The work done on the particle by this force is: A 20J F _>, e» w», P. m B)101 kad’am W: {7.31" agar—‘2: grind C) “20] D) 301 {r _ E) none of these 3 @555” j r 20 ‘J Page 2 5. The diagram shows a velocity-time graph for a car moving in a straight line. At point P the car must be: AV! 4!: r A) moving with constant velocity , B) slowingdown div ['5 ﬁestilvi’r f? 7% D) stationary CL> g E) in reverse 6. A crate weighing 400 N rests on a rough horizontal ﬂoor. A 120 N horizontal force is then applied to it. If the coefﬁcient of static friction is 0.5 and the coefﬁcient of kinetic friction is 0.4, the magnitude of the frictional force on the crate is: A) SON ‘ 1m Mamiwwn {wee cgwa ‘lT'D Siai‘lc. C) 160N {imam i: T. (0.5) x 4.00 N D) 200N E) 400N 3 200M Maw mm 4 200M FY“: Wcé :- l2 0 l\l 7. A dart is thrown horizontally toward X at 20 m/s as shown. It hits Y 0.1 5 later. The distance XY is: 3)) = aaiow/Sx C) 0.5m 2 D 0.1m i ‘— " _. —-l J) 'm : O‘OS/ mm Page 3 8. 10. An object is thrown straight up from ground level with initial speed 50 m/s. If g = 10 111/82, its distance above ground level 1.0 s later is: ~1A 40mg am ‘f C) m , I I 1 D) 55m ~ ﬁujzargﬁ ' 331’. E) 60m “350 7 L_\ 4, 15b”, £00390) rim ‘1- - 5) 'm d 43m A pendulum bob of mass m is held at an angle 6 ﬁrom the vertical orizontal force F as shown. The magnitude of the force F is given by: ‘9‘] WWW Eﬁ‘x s ._,‘ a s F A) mgcost’il B) m sine? D)‘ mgcosﬂ T0369 2 E) none ofthese 1’ 3M9 = F 2 m5 1 F C639 Si'nQ F— "; ma {61449 In a centrifuge a sample moves in a circular trajectory at high speed. If the radius of the circle is 0.25 m, approximately what is the speed of the sample if its centripetal acceleration is 20g? A) 1m/s c 4 Emma “anagram a: v1 ,r. . . _..__ B) 3m/s a“ "1" ® 41:? (1": O.2S")~'\ 0.220% D) 1211315 B) ZOm/s ___ 200M373. (6 1 I \l 2001“ = ‘U [51 6525‘?“ Page 4 11. A 50 N force acts on an object of mass 2.0 kg, which was initially at rest. No other 12. Three blocks (A,B,C), each having the same mass M, are connected by strings as shown. 13. force acts on the object, which begins to accelerate when the force is applied. At the instant 2.0 s after the force began to be applied, what is the rate at which the force is doing work (i.e., what is the power)? A) 50 W a a B) 400w "wa ’33- F-V F C) meow {,3 l1? -.- at a 7;: t 1 a E) sooow \i —.= it: #2. m a. Lg “(Hr 1 a; 5°) X2 w 2. :' 2500 ‘w’ Block C is puiled to the right by a force 17 that causes the entire system to accelerate. Neglecting friction, what is the tension in the string that connects blocks A and B? A) zero k @ acceleroi‘m 30»: C) F/2 9» D) 2F/3 «r E) none of these _,JEij——- “T f- M Q" = .E 3 A projectile is shot vertically upward with a given initial velocity. It reaches a maximum height of 1000 m. If, on a second shot of the same projectile, the initial velocity is one- half the value of the initial velocity on the ﬁrst shot, then the projectile will reach a maximum height of: A) 50011) tact); rut—at: to => t: ) 400 “Kim = ant- grain. E) none of these EV a; m .; w, __ .3. ... moo rm “ﬂCt “ 2 2 "L i -i we : 320000 ’“""‘/31 fl r l J . l l “'1‘?” “ﬁt-D Snot. a? :7: WKEQOOO 1 {51 .53 i E 57100 n P 5 *L N} :2 ‘— try“ age Limit 22 to We 2 14. A crate of mass 25 kg is resting on a horizontal plank. The coefﬁcient of static friction is 15. 16. 0.40 and the coefﬁcient of kinetic friction is 0.20. After one end of the plank is raised so the plank makes an angle of 30° with the horizontal, the acceleration of the crate down the plank is about: 3)) (1)111st slum" x {1‘3 N . 2 t r ﬂ {E g Whatth juice M \$9 3 E) 4.4111/32 r: {us (“ﬂ :lbis’mat-® :3 \$22.13;»: as N >896 N peg mm m 300 43.3»; Mcaiawtﬁ'm. a = i2 g .3 suppose A = 3'10", Where A has dimensions LT, B has dimensions L71”, and C has dimensions LTz, where L represents length and T represents time. Then the exponents n and m have the values: «hith am a: “:93 *0/51: 3.31m A) 2/3; 1/3 5, L1“ lem H Lzmw Tam-“ B) 2;3 LT ‘= {5-1:} (L ” c 4/5-1/5 E) 1/2; /2 2h. +m : 1 2m — n a “J— ~ ‘2‘- Tn 2: ﬁg- ? S- An object of mass 2.0 kg is initially at rest. Then a constant force of 5.0 N is exerted for 4.0 s on the object. What will the speed of the object be at the end of this period? A) 0.5m/s C) 5111/5 Z \ D ) 5-7." vat) :- vs + at: =- o + :3;st Wig 2 :1 iQ‘fﬂfS Page 6 ...
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