Physics 105 Exam 2 10/31/2008 Name A

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1 Physics 105 Exm 2 10/31/2008 Nme_ A As student t NJIT I will conduct myself in professionl mnner nd will comply with the proisions of the NJIT Acdemic Honor Code. I lso understnd tht I must subscribe to the following pledge: On my honor, I pledge tht I he not iolted the proisions of the NJIT Acdemic Honor Code. Multiple Choice: (15 questions, 1pt. ech) Identify the letter of the choice tht best nswers the question. 1. When certin force is pplied to n object with mss of 2 kg, its ccelertion is 10.0 m/s 2. When the sme force is pplied to different object, its ccelertion is 4.0 m/s 2. The mss of second object is kg b. 8.0 kg c. 5.0 kg d. 2.5 kg e kg 2. If firefly collides with the windshield of fst-moing bus, which sttement is correct?. The firefly experiences n impct force with lrger mgnitude b. The bus experiences n impct force with lrger mgnitude c. The firefly nd bus experience forces with sme direction d. The firefly nd bus experience forces with sme mgnitude e. None of the boe 3. A hey weight is supported by two cbles tht exert tensions of mgnitude T 1 nd T 2. Which sttement is correct?. T 1 = T 2 b. T 1y = T 2y c. T 1 < T 2 d. T 1 > T 2 e. We need the mss of the box in order to determine the correct nswer 4. The tension in string from which 4.0-kg object is suspended in n eletor is equl to 44 N. Wht is the ccelertion of the eletor?. 11 m/s 2 upwrd b. 1.2 m/s 2 upwrd c. 1.2 m/s 2 downwrd d. 10 m/s 2 upwrd e. 2.4 m/s 2 downwrd

2 Physics 105 Exm 2 10/31/2008 Nme_ A 5. Wht is the smllest lue of the force F such tht the 2.0-kg block will not slide down the wll? The coefficient of sttic friction between the block nd the wll is N b. 20 N c. 10 N d. 4 N e. 2 N F 6. In gme of shufflebord (plyed on horizontl surfce), puck is gien n initil speed of 6.0 m/s. It slides distnce of 9.0 m before coming to rest. Wht is the coefficient of kinetic friction between the puck nd the surfce? b c d e A block is pushed cross horizontl surfce by the force F with constnt elocity. F = 20 N, θ = 30, nd M = 10 kg. Wht is the mgnitude of the norml force on the block?. 20 N b. 88 N c. 94 N d. 98 N e. 108 N 8. A 3.0-kg block slides on frictionless 20 inclined plne. A force of 16 N cting prllel to the incline nd up the incline is pplied to the block. Wht is the ccelertion of the block?. 2.0 m/s 2 down the incline b. 5.3 m/s 2 up the incline c. 2.0 m/s 2 up the incline d. 3.9 m/s 2 down the incline e. 3.9 m/s 2 up the incline

3 Physics 105 Exm 2 10/31/2008 Nme_ A 9. If F = 40 N nd M = 1.5 kg, wht is the tension in the string connecting M nd 2M? Assume tht ll surfces re frictionless.. 13 N b. 23 N c. 36 N d. 15 N e. 28 N 10. A bll is moing in clockwise direction round circle t constnt speed. Which digrm correctly shows the directions of its elocity ector () nd ccelertion () when the bll is locted t tht point on the circle?. b. c. d. e. 11. A roller-coster cr hs mss of 500 kg when fully loded with pssengers. At the bottom of circulr dip of rdius 40 m (s shown in the figure) the cr hs speed of 16 m/s. Wht is the mgnitude of the force of the trck on the cr t the bottom of the dip?. 3.2 kn b. 8.1 kn c. 4.9 kn d. 1.7 kn e. 5.3 kn 12. An irplne flies in horizontl circle of rdius 500 m t speed of 150 m/s. If the plne were to fly in the sme 1000 m circle t speed of 300 m/s, by wht fctor would its centripetl ccelertion chnge? b c d e. 4.00

4 Physics 105 Exm 2 10/31/2008 Nme_ A 13. If the coefficient of sttic friction between the tires nd rod on riny dy is 0.5, wht is the fstest speed t which cr cn mke turn with rdius of 80.0 meters? The rod is flt.. 7 m/s b. 11 m/s c. 14 m/s d. 20 m/s e. 25 m/s 14. A 5-kg bll hngs t one end of string tht is ttched to support on rilrod boxcr. When the boxcr ccelertes to the right, the string mkes n ngle of 30 with the erticl. The ccelertion of grity is 9.8 m/s 2 nd ir resistnce is negligible. Find the ccelertion of the boxcr m/s 2 b m/s 2 c m/s 2 d. 9.8 m/s 2 e. 5.7 m/s A boy on bord cruise ship drops 30.0 grm mrble into the ocen. If the resistie force proportionlity constnt is 0.50 kg/s, wht is the terminl speed of the mrble in m/s? b c d e

5 Physics common exm #2 10/31/2008 A Answer Section MULTIPLE CHOICES 1. ANS: C DIF: 1 Newton s Second Lw 2. ANS: D DIF: 2 Newton s Third Lw 3. ANS: D DIF: 2 Blnced Forces 4. ANS: B DIF: 2 Object under Net Force 5. ANS: A DIF: 2 Sttic Friction 6. ANS: A DIF: 2 Kinetic Friction 7. ANS: E DIF: 2 Object in Equilibrium 8. ANS: C DIF: 2 Object on n Inclined Surfce 9. ANS: B DIF: 2 Multiple Objects 10. ANS: D DIF: 2 Uniform Circulr Motion 11. ANS: B DIF: 2 Centripetl Force 12. ANS: D DIF: 2 Centripetl Accelertion 13. ANS: D DIF: 2 Centripetl Force nd Friction 14. ANS: E DIF: 2 Motion of Accelerted Frme of Reference 15. ANS: C DIF: 2 Motion in the Presence of Resistie Force