Physics 30: Chaper 2 Exam Momenum & Impulse Name: Dae: Mark: /29 Numeric Response. Place your answers o he numeric response quesions, wih unis, in he blanks a he side of he page. (1 mark each) 1. A golfer pus a 45.7 g golf ball a speed of 1.10 m/s along a level green. Deermine he magniude of he ball s momenum. 50.3 gm/s 2. A 20 g ball is dropped from a heigh of 1.2 m. Deermine is momenum jus as i his he ground. 97 gm/s down 3. A curler slides a 20 kg curling rock a a speed of 2.0 m/s. The rock is caugh by a saionary 55 kg player. If fricional losses are ignored, deermine he speed of he player immediaely afer caching he rock. 4. A 10 kg mass moving wih a kineic energy of 150 J collides wih a 15 kg mass having a kineic energy of 100 J. Assuming he collision is inelasic and he 10 kg mass has 90 J of kineic energy afer he collision. Deermine he amoun of kineic energy possessed by he 15 kg mass afer he collision if 80 J of hea energy is released during he collision. 80J Copyrigh (c) Kennedy, 2008 1
Wrien Response. Show all your work. Clearly idenify your final answer(s) rounded off o he proper number of significan digis. 1. A 12 kg mass is sliding due eas a 2.0 m/s when i collides wih a saionary 10 kg mass. Afer he collision he 12 kg mass is moving wih a velociy of 1.2 m/s, 24 S of E. a. Deermine he velociy of he 10 kg mass afer he collision. (5 marks) b. Show ha he collision was inelasic. (2 marks) Copyrigh (c) Kennedy, 2008 2
Muliple Choice. Selec he bes answer and mark i clearly on your Scanron. (1 mark each) 1. An alpha paricle (6.65 x 10-27 kg) is ravelling a 4.50 x 10 6 m/s. The magniude of is momenum is a. 2.99 x 10-20 kg m/s b. 1.48 x 10-33 kg m/s c. 2.99 x 10-22 kg m/s d. 1.48 x 10-22 kg m/s 2. A 400 g ball is dropped from a heigh of 95 cm. Calculae he magniude of is momenum as i makes conac wih he floor. a. 1.7 kg m/s b. 4.3 kg m/s c. 7.5 kg m/s d. 17 kg m/s 3. A 640 g oy car moving eas has a kineic energy of 0.348 J. The magniude of is momenum is a. 0.667 kg m/s b. 0.223 kg m/s c. 0.696 kg m/s d. 0.472 kg m/s 4. A baseball has a momenum of 3.0 kg m/s norh before i is hi. Deermine he impulse acing on he ball while i is being hi if is momenum afer being hi is 5.0 kg m/s o he souh. a. 2.0 N s o he norh b. 2.0 N s o he souh c. 8.0 N s o he norh d. 8.0 N s o he souh Use he following informaion o answer quesions 5 & 6. A 150 g baseball is piched horizonally o he norh a a speed of 30.0 m/s. Afer he baer his he ball i moves horizonally o he souh a a speed of 30.0 m/s. 5. Deermine he magniude of he impulse ransferred o he ball. a. 0 N s b. 4.5 N s c. 9.0 N s d. 135 N s 6. Deermine he magniude of he average force exered on he ball by he ba if hey were in conac for 0.900 s. a. 10.0 N b. 150 N c. 135 N d. 5.00 N Copyrigh (c) Kennedy, 2008 3
7. A pendulum is released from a verical heigh of 30 cm. The maximum momenum of he pendulum can be found using he expression a. p = m 2gh b. p = m 1 2 gh c. p = 2mgh d. p = m gh 8. The unis of momenum can be expressed as a. kg m/s 2 b. N/s c. N m/s d. kg m/s Use he informaion below o answer quesion 9. The graph below shows he ne force of a paddle in waer causing a kayak o ravel along a sill lake. 500 Ne Force versus Time Force (kn) 0 Time (s) -500 1.0 2.0 9. The ne impulse on he paddle is a. 230 kn s b. 460 kn s c. 500 kn s d. 540 kn s 10. Impulse may be defined as a. an objecs momenum b. he work done on an objec per uni ime c. a produc of force and ime d. force per uni ime Copyrigh (c) Kennedy, 2008 4
11. Idenify he lis below ha conains only conserved quaniies. a. Energy, acceleraion, forces b. Energy, momenum, velociy c. Momenum, mass, energy d. Momenum, velociy, forces Use he following informaion o answer quesion 12. Ballisic pendulums used o be used o deermine a firearm s muzzle velociy. A ballisic pendulum is consruced by hanging a block of wood by wo wires; he wires allow he block o swing freely like a pendulum. A 3.50 kg rifle fires a 20.0 g bulle ino a ballisic pendulum as shown in he diagram below. The bulle buries iself in he 1.80 kg ballisic pendulum, and hey rise o a verical heigh of 0.350 m. 0.70 m 12. Deermine he bulle s muzzle velociy (i.e., speed he bulle leaves he rifle barrel). a. 2.62 m/s b. 236 m/s c. 238 m/s d. 262 m/s 13. Two idenical air pucks collide a righ angles and sick ogeher. Each has a momenum of 2.0 kg m/s before he collision. Deermine he magniude of heir momenum afer he collision if hey sick ogeher upon impac. a. 2.0 kg m/s b. 2.8 kg m/s c. 4.0 kg m/s d. 8.0 kg m/s 14. Idenify he rue saemen below. a. kineic energy and momenum are boh conserved in inelasic collisions b. only kineic energy is conserved in elasic collisions c. kineic energy and momenum are boh conserved in elasic collisions d. only momenum is conserved in elasic collisions Copyrigh (c) Kennedy, 2008 5
Use he informaion below o answer quesion 15. A oy conains hree differen springs ha cause he oy o come apar ino hree idenical pieces ha all move along he floor as shown in he diagram below. N 2.0 m/s 45 3.0 m/s 15. Predic he direcion ravelled by he hird piece of he oy. a. 74 S of E b. 87 W of N c. 13 N of W d. 87 N of E Use he informaion below o answer quesions 16 & 17. A 40 kg mass moving wih a kineic energy of 200 J collides wih a 15 kg mass having a kineic energy of 180 J. 16. Assume he collision is compleely elasic and he 40 kg mass has 180 J of kineic energy afer he collision. Deermine he amoun of kineic energy possessed by he 15 kg mass afer he collision. a. 0 b. 20 J c. 180 J d. 200 J 17. Assuming he collision is inelasic and he 40 kg mass has 140 J of kineic energy afer he collision. Deermine he amoun of kineic energy possessed by he 15 kg mass afer he collision if 100 J of hea energy is released during he collision. a. 0 b. 50 J c. 150 J d. 230 J Copyrigh (c) Kennedy, 2008 6
Use he following informaion o answer quesion 18. A sone is hrown sraigh up ino he air and falls under he influence of graviy. The following six graphs may represen he sone s moion as i ravels freely hrough he air (ignore air resisance). A B C D E F 18. Idenify he graph ha bes displays he momenum of he sone as a funcion of ime. a. F b. D c. A d. E Copyrigh (c) Kennedy, 2008 7
Sas Class average on muliple choice: 67% Quesion answer % Correc Quesion answer % Correc 1 a 100 16 d 81 2 a 85 17 c 69 3 a 100 18 b 4 d 70 5 c 74 6 a 78 7 a 66 8 d 96 9 b 67 10 c 63 11 c 52 12 c 44 13 b 26 14 c 67 15 d 44 Copyrigh (c) Kennedy, 2008 8