First Semester Review for Physics

Transcription

1 First Semester Review fr Physics Learning gals are written in italics, practice exercises are numbered. Yu will find the equatins n the last page. Shw wrk fr all calculatins by writing Given, Find, Equatin in term f the unknwn, substitutin f values with units and Check. Yu shuld answer questins n separate sheets f paper. Keep this rganized. Sectin 2.2 Cnstant Speed and Acceleratin Define vectr and scalar and use definitins t differentiate between them. 1. What is the difference between distance and displacement. Explain difference between average and instantaneus velcities and speeds 2. Prvide a scenari in which the average speed f a runner is greater than its instantaneus speed. Define in wrds, and equatin: average and instantaneus, velcity and speed. Differentiate between them. 3. Explain the difference between velcity and speed 4. Explain why is it pssible fr a truck that cllects milk frm farms t have an average velcity f 20.0 miles/hur if when its minimum speed while in mtin was 30.0 miles/hur Slve prblems arund average velcity using the crrect equatin by writing Given, Find, Equatin in term f the unknwn, substitutin f values with units and Check. 5. Find the average velcity f a race car that starts 15 m behind the starting pint and is m in frnt f the starting pint 3 secnds later. 6. Calculate the time it takes a plice cruiser t cver 50.0 km at an average speed f 80.0 km/h. Define average acceleratin in wrds and equatin 7. Explain what happens t the velcity f an bject that starts frm rest and accelerates at -10.0m/s 2 Slve prblems arund average acceleratin using the crrect equatin by writing Given, Find, Equatin in term f the unknwn, substitutin f values with units and Check. 8. What is the final velcity after 3.0 secnds f an bject that accelerates at -9.8 m/s 2? 9. A mtinless space craft begins t fall twards an explanet (a planet utside f ur planetary system). Calculate the average acceleratin if given that it reaches 50 m/s in just 3.0 s 10. What is the acceleratin f an bject whse velcity ges frm 55 m/s t 30 m/s in 5.0 s? 11. What wuld be the final velcity fr a swimmer that accelerates at 3 m/s 2 frm an initial velcity f -10 m/s after 4.0 s? 1

2 Sectin 1.2 Measurement Describe uncertainties in measurements 12. Explain what is meant by uncertainty in measurements? Describe and explain the differences in accuracy and precisin. 13. Prduce a set f measurements that are a. Accurate, but nt precise. Make sure t explain why yu did what yu did. b. Precise, but nt accurate. Make sure t explain why yu did what yu did. Describe the difference between randm and systematic errrs in measurements 14. Give an example f systematic errr in a set f measurements, and an example f randm errr in a set f measurements. Explain the need fr significant figures by describing precisin and uncertainty 15. Use the wrds precisin and uncertainty t explain why 235s x 1 = 200s 16. Determine the number f significant figures fr: a. 0 m/s b..004 g c kg d s Apply significant figures t all calculatins e m f N g s 17. Find the answer with the crrect number f significant figures. Calculatr answer given. h. 456 m * m = m 2 =? i. 500 N /25. Kg =12,500 m/s 2 =? j kg x m/s 2 = N =? k... = 420 m/s =? l mm * 1 mm = mm 2 =? m g g = g =? n. 7.0 m m = m =? Distinguish between quantitative and qualitative bservatins 18. Tw students are watching a kicker practicing kicking field gals. One student is making quantitative bservatins f the frce, and acceleratin, initial velcity and final velcity f the kicked ftballs, while the secnd student is making qualitative bservatins f the frce, acceleratin, initial and final velcities f the kicked ftbals. Write dwn what a set f quantitative bservatins the first student might write dwn, and the matching set f qualitative bservatins the secnd student might write dwn. Sectin 2.1 Newtn s First law Explain what inertia is and hw we measure it. 19. Explain why increasing the speed f an bject des nt increase the inertia f an bject. 2

3 Describe Newtn s 1 st Law f mtin. 20. Using Newtn s 1 st Law, explain why a sccer ball when kicked will eventually cme t a stp, instead f ging n frever. Explain what is meant by frame f reference and prvide a situatin that illustrates this. 21. One student sees a car and says the car is mving at 29 m/s nrth, while anther student sees the same car and says the car is nt mving. Explain hw bth students can be crrect in their descriptins f the car. Slve Vectr additin prblems within frame f reference. 22. A train is mving at 15 m/s t the right. A persn n the train thrws a ball at 5.0 m/s t the right.. What speed wuld the peple n the train measure fr the thrwn ball? p. What speed wuld a persn standing utside the train measure fr the thrwn ball? Sectin 2.3 Newtn s Secnd law Differentiate between mass and weight f an bject 23. Explain the difference between mass and weight f an bject 24. Explain hw can the weight f an bject change while the mass remains cnstant? Describe Newtn s Secnd Law 25. Accrding t Newtn s secnd law, if I want tw bjects f different mass t have the same acceleratin, which bject shuld receive a strnger frce, the mre massive r least massive? Explain using Newtn s 2ns Law. Use Newtn s secnd law t calculate mass, acceleratin, and frce n an bject Calculate the weight, mass, r acceleratin due t gravity 26. Determine the mass f the tennis ball that accelerates frm rest at 2500 m/s 2 when a frce f 143 N is applied. 27. Determine the weight f an bject with 3 kg f mass if its speed increases dwnwards m/s 2 every secnd when in free fall. Identify the units used t describe frces 28. What is the equivalent f 1 Newtn in terms f kilgrams, secnds and meters 29. Explain hw culd yu figure ut the equivalence f 1 Newtn in terms f kilgrams, secnds and meters by lking at Newtn s Secnd Law ( = ) Add frce vectrs acting at right angles r parallel t each ther using bth the tip-t-tail methd and mathematically. 30. Tw players n a rugby scrum push against each ther. One pushes with 300. N t the right f the field, and the ther with 200. N t the left. What is the net frce (include directin)? 31. What is the resultant frce n a swimmer that prpels herself with 400. N t the nrth if she is swimming n a sea current that pushes her with 150. N t the East? 3

4 Sectins 4 and 5 Prjectile Mtin Describe the difference between free fall and prjectile mtin 32. What is the difference between free fall and prjectile mtin? Draw and describe the psitin vs time f a prjectile and an bject in free fall 33. If a prjectile is fired hrizntally and anther is drpped at the same time, which ne will hit the grund first? Draw a diagram t defend yur answer and explain yur answer in wrds. Describe hw vertical and hrizntal mtins are cnnected in prjectile mtin. 34. Hw are the vertical and hrizntal mtins in f a glf ball in flight related? Identify the frce acting n a prjectile 35. What is the nly frce acting n a ftball after it is kicked? Identify the vertical acceleratin n a prjectile 36. What is the vertical acceleratin n a baseball after it has been hit with a bat? Identify the hrizntal acceleratin n a prjectile 37. What is the hrizntal acceleratin n a baseball after it has been hit with a bat? Predict the angle that will prvide the maximum range fr a prjectile when launched frm the grund. 38. What angle will prduce the maximum range fr a prjectile? Reslve velcity f an bject int its vertical and hrizntal cmpnents 39. A ftball is kicked at 19.5 m/s at an angle f 72. Determine the hrizntal and vertical velcity. Describe the factrs that affect the time a prjectile stays in the air. 40. List at least three factrs that affect the time a prjectile stays in the air Describe the factrs that affect the range f a prjectile 41. List tw factrs that affect the range f a prjectile Knw the final vertical velcity at peak and at end f parablic flight. 42. A glf ball is hit with and initial vertical velcity f 29 m/s. What is the vertical velcity at the peak f its flight, and the vertical velcity at the end f its parablic flight? 4

5 Slve mathematical prblems n prjectile mtin including the fllwing: Reslve velcity f an bject int its vertical and hrizntal cmpnents Use vertical cmpnent f mtin t find the time the prjectile is in the air until: Maximum height Overall time Use time t maximum height t get maximum height reached by prjectile Use hrizntal cmpnent f velcity and time in the air t find hrizntal displacement (range). 43. A vlleyball is bumped straight up at 15 m/s. Hw lng will it take the vlleyball t reach its highest pint? 44. A kick ball is kicked at an angle f 23 at 32 m/s. q. What are the hrizntal and vertical cmpnents f the initial (net) velcity? r. What is the time t the maximum height? s. What is the maximum height reached f the kick ball? t. What is the time fr the entire flight? u. What is the range f the kick ball? Sectins 2.6 Newtn s 3 rd Law Describe Newtn s 3 rd Law 45. Explain what frce causes a persn n a skatebard t mve when the persn pushes n a wall. Explain where des a pair f frces act. 46. Explain hw if frces always cme in pairs, hw can any bject be accelerated (experience a net frce)? Draw Free Bdy Diagrams 47. Draw the Free Bdy Diagram n bth a sccer player and a sccer ball when the player kicks the sccer ball t the right. Make sure t label each frce yu draw in each free bdy diagram. Describe physical situatins using Newtn s 3 rd Law. 48. Describe the frce that causes a persn t accelerate frm a standing psitin t walking. Sectins 2.7 Frictin and Inclined plane Define frictin 49. What is frictin Describe the difference between static and sliding (kinetic) frictin 50. What is the difference between static and sliding (kinetic) frictin? 5

6 Describe the frce nrmal t the surface 51. Sketch a she n a hrizntal surface and an inclined surface and then draw in the nrmal frce acting n the she in sketches. Slve mathematical prblems that invlve frictin including free bdy diagrams 52. A quarterback f mass 88 kg runs fr a first dwn and then slides t a stp t avid getting hit. The cefficient f frictin between the grund and the quarterback is knwn t be v. Draw and clearly label a freebdy diagram fr the quarterback. w. Determine the nrmal frce acting n the quarterback. x. Calculate the frce f frictin that caused the quarterback t stp. 53. A skier f weight 835 N glides dwn a cnstant slpe f 7.4 y. Draw and clearly label a freebdy diagram fr the skier. z. Determine the magnitude f the weight frce that is parallel t the slpe. aa. Determine the magnitude f the weight frce that is perpendicular t the slpe. bb. Determine the ceffiecient f sliding (kinetic) frictin fr this situatin. = =, = + 2, = =, = sin = h cs = h tan = 6