Phys 111 Exam 1 September 18, You cannot use CELL PHONES, ipad, IPOD... Good Luck!!! Name Section University ID

Transcription

1 Phys 111 Exam 1 September 18, 018 Name Section University ID Please fill in your computer answer sheet as follows: 1) In the NAME grid, fill in your last name, leave one blank space, then your first name. ) Write your ID number in the IDENTIFICATION NUMBER section of the sheet. 3) Write your recitation section number in the spaces K, L in the SPECIAL CODES section. Single digits should be preceded by a 0 (e.g. section 1 is written as 01). 4) Fill in the circles on the sheet corresponding to the letters or numbers of your name, ID and section with a # pencil. Note (a) Use g = 9.81 m/s if needed. (b) There are 0 multiple choice problems. (c).0 hour Exam (no one can leave before 9:15 PM). (d) Formula sheets are available (attached at the last two pages). (e) Record sheet is attached after the 0 exam problems. You cannot use CELL PHONES, ipad, IPOD... Good Luck!!! 1

2 cm can also be expressed in mm as (A) mm. (B) mm. (C) mm. (D) mm. (E) mm.. Convert a speed of 4.50 km/h to units of ft/min. (1.00 m = 3.8 ft) (A) 0.46 ft/min (B) 8.3 ft/min (C) 165 ft/min (D) 46 ft/min (E) 886 ft/min 3. Suppose that an object travels from one point in space to another. Make a comparison between the magnitude of the displacement and the distance traveled by this object. (A) The displacement is either greater than or equal to the distance traveled. (B) The displacement is always equal to the distance traveled. (C) The displacement is either less than or equal to the distance traveled. (D) The displacement can be either greater than, smaller than, or equal to the distance traveled. (E) None of them. 4. The graph in the figure shows the position of an object as a function of time. The letters H-L represent particular moments of time. At which moment in time is the speed of the object equal to zero? (A) H (B) I (C) J (D) K (E) L

3 5. A car accelerates from to at a constant rate of How far does it travel while accelerating? (A) 69 m (B) 07 m (C) 41 m (D) 117 m (E) 10.5 m 6. A bullet shot straight up returns to its starting point in 10 s. What is the initial speed of the bullet, assuming negligible air resistance? (A) 9.8 m/s (B) 5 m/s (C) 3 m/s (D) 4 m/s (E) 49 m/s 7. The figure shows a graph of the velocity of an object as a function of time. What is the acceleration of the object at 3.0 s? (A) 10 m/s (B) 5.0 m/s (C) 0 m/s (D) -5 m/s (E) -10 m/s 8. Consider two vectors and shown in the figure below. The difference - is best illustrated by (A) choice (a). (B) choice (b). (C) choice (c). (D) choice (d). 3

4 9. A stone is thrown horizontally with an initial speed of 10 m/s from the edge of a cliff. A stopwatch measures the stone's trajectory time from the top of the cliff to the bottom to be 4.3 s. What is the height of the cliff if air resistance is negligibly small? (A) m (B) 43 m (C) 77 m (D) 91 m (E) 98 m 10. A boy throws a rock with an initial velocity of at 30.0 above the horizontal. How long does it take for the rock to reach the maximum height of its trajectory if air resistance is negligibly small? (A) s (B) 0.8 s (C) s (D) s (E) 0.30 s 11. Alicia intends to swim to a point straight across a 100 m wide river with a current that flows at 1. m/s. She can swim.5 m/s in still water. At what angle, measured from the upstream direction, must she swim upstream to achieve her goal? (A) 9 (B) 61 (C) 45 (D) 0 (E) An astronaut weighs 99 N on the Moon, where the acceleration of gravity is 1.6 m/s. How much does she weigh on Earth? (A) 9.8 N (B) 16 N (C) 99 N (D) 600 N (E) 970 N 13. A catcher stops a 0.0-kg ball traveling at 40 m/s in a distance of 0 cm. What is the magnitude of the average force that the ball exerts against his glove? (A) 16 N (B) 61 N (C) 99 N (D) 600 N (E) 800 N 4

5 14. A 10-kg sign is held by two ropes as shown in the figure. What is the tension on rope A? (A) 44 N (B) 69 N (C) 7 N (D) 88 N (E) 98 N 15. In the figure, block A has a mass of 3.00 kg. It rests on a smooth horizontal table and is connected by a very light horizontal string over an ideal pulley to block B, which has a mass of.00 kg. When block B is gently released from rest, how long does it take block B to travel 80.0 cm? (A) s (B) s (C) s (D) s (E) s 16. A box is given a push so that it slides across the floor. Haw far will it go, given that the coefficient of kinetic friction is 0.15 and push imparts an initial speed of 3.5 m/s. (use g= 9.80 m/s ) (A) 0.53 m (B) 4. m (C) 1.5 m (D) 0.18 m (E) 4 m 17. According to a simplified model of a mammalian heart, at each pulse approximately 0 g of blood is accelerated from 0.5 m/s to 0.35 m/s during a period of 0.10 s. What is the magnitude of the force exerted by the heat muscle? (A) 0.0 N (B) 0. N (C) 0.1 N (D) 0.01 N (E) 0.4 N 5

6 18. Two forces act on a object. One force has magnitude 65 N directed 59 clockwise from the positive x-axis, and the other has a magnitude 35 N at 3 clockwise from the positive y- axis. What is the magnitude of this object's acceleration? (A) 0.9 m/s (B) 1.1 m/s (C) 1.3 m/s (D) 1.5 m/s (E) 1.7 m/s 19. The figure shows velocity versus time for a runner. How far does the runner travel in 0 s? (A) 10 m (B) 0 m (C) 30 m (D) 55 m (E) 65 m 0.. A locomotive is pulling three wagons along a level track with a force of F=100,000 N. The wagon next to the locomotive has a mass of m 1 =80,000 kg, the next one, m =50,000 kg, and the last one, m 3 =70,000 kg. Neglect friction. What is the force between the 80,000-kg and 50,000-kg wagons? F m 1 m m 3 (A) 35,000 N (B) 40,000 N (C) 50,000 N (D) 60,000 N (E) 65,000 N 6

7 Record Sheet of Exam 1, Physics 111, Fall 018 You may fill in this sheet with your choices and take it with you for comparison to the posted answers

8 Physics 111, Fall 018: Formula sheet Vectors: A Acos A Asin x y 1 x y tan Ay / Ax A A A Linear Motion: x x f xi v x / t a v / t v v0 at 1 1 x v0t a t v v0 a x x v0 v t v 0 Range; R sin g Forces: N Fnet mm 1 Fnet F1 F F3 Fi a Fg G i1 m r Weight W mg fk kn fs sn Fx kx Work and Energy: W ( F cos ) d KE mv / PE mgh P work / t Fd / t Fv Etot KE PE PE kx / Linear momentum and impulse: p mv Ft p I Ft p p 0 p f pi x m x / m cm i i i y m y / m cm i i i Uniform Circular Motion: v r / T a v / r c F c mv / r tan v / rg Rotational Kinematics: s/ r / t / t 0 t T / 1 0t t vt r t r 0 ac r Rotational Dynamics: rsinf L 0 Lf Li I miri I L / t L I KE R I / W Gravity: F Gm m r g 1 / G Nm kg / / g 1 PE U Gm m r KE mv / Oscillations about equilibrium: f F kx x Acos( t); vx Asin( t); ax Acos( t) T k L E KE PE mv kx ka T m g

9 Waves and Sound: F m P P v f v ; I T L A 4 r n log( AB) log( A) log( B); log( A/ B) log( A) log( B); log(10 ) n (10 db)log( I / I ); I 10 W / m Doppler Effect for moving source: f0 fs (-) source moving towards observer 1 vs / v v0 Doppler Effect for moving observer: f0 fs 1 (+) observer moving towards source v Constructive Interference: d1 d n; n 0,1,,3,... Destructive Interference: d1 d n ; n 1,3,5,... Standing waves on a string of length L = Standing waves in a column of air open at both ends of length L L v v n ; fn n ; n 1,,3,... n n L Standing waves in a column of air closed at one end of length L 4 L v v n ; fn n ; n 1,3,5,... n 4L Beat Frequency: fbeat f1 f n Fluids: M F 5 ; P ; Pgauge P Patm ; Patm N / m V A P P gh 1 FBuoyant fluidvg ; FBuoyant fluidvg m1 m Conversation of Mass : 1 A1 v1 A v t t 1 1 Bernoulli ' s Equation : P1 v1 gy1 P v gy Temperature and Heat: 5 TC TF 3 TK TC 73.15; L L0T ; V V0T ; Q mct Q ml ; Q ml ; Q / t kat / L; Q / t eat ; W / ( m K ) fusion f vaporization v Ideal Gases: 3 PV nrt Nk T; n N / N m / ( mass per mole); R 8.31 J / ( mol K); k J / K B A B NA molecules / mole; KEav ( mv ) av kbt; U nrt NkBT Thermodynamics: U Q W; W PV ; CV 3 R / ; CP 5 R / ; CP / CV 5/ 3 W Qh Qc Qc Tc Qh Qc e 1 1 ; COP ; Air Conditioner COP Qh Qh Qh Th W W Q Qh Qc S ; Stotal 0 T T T h c