LAHS Physics Semester 1 Final Review Information

Transcription

1 LAHS Physics Semester Final Reiew Infrmatin Yur Semester Physics Final has tw parts as fllws: Part I - Multiple Chice Questins - (Indiidually, 50 minutes) Part II - Free Respnse Questins - (Assigned pairs annunced st Mn f Dec, 50 minutes) Yur Semester grade will be calculated as fllws: Quarter percentage = 40% f grade Quarter percentage = 40% f grade Semester Final Part I = 0% f grade Semester Final Part II = 0% f grade It is highly recmmend that yu study/reiew in small grups well ahead f yur scheduled Final, preferably with yur assigned partner s that yu can wrk ut cllabratin and cperatin details ahead f time. Arrange fr tutring help with yur teacher r tutrs at the Tutrial Center. If yu happen t miss any part f the Final fr any reasn, expect t d the make-up exam(s) ALONE. Part I - Multiple Chice Questins The first 50 minutes f yur written final n yur scheduled 00-minute perid will be a Multiple Chice sectin. Yu will d this part by yurself. The questins are cnceptual and quick mathematical prblems with the purpse f assessing hw well yu understand the cncepts discussed thrughut the semester. It is a scantrn exam with n partial credit fr wrng answers. If yu dn't knw the answer, yu are encuraged t guess. There is n penalty fr guessing unlike sme ther types f exams. Part II - Free Respnse Questins The purpse f the Free Respnse Sectin f the Final is t assess yur ability t sle prblems. Yu will d this part with yur assigned partner. This packet includes a set f reiew prblems fr yu t study. On the Mnday f Finals Week, 6 f these reiew prblems will be annunced as prblems fr yu t prepare at hme a perfect slutin fr grading. Then at the beginning f the last 50 minutes f the Final, yu will be asked t submit nly ne f the 6 perfect slutins. This prblem will be randmly chsen fr each perid and culd be different fr eery Physics class. This ne prblem cunts as ne f the Free Respnse slutins t be graded. Fr the in class prtin f the Free Respnse part f the Final, yu will be asked t write yur perfect slutin t ne f the remaining reiew prblems in this packet nt preiusly annunced n the Mnday f Finals Week. The numbers gien in the prblem will be changed slightly fr the real test, but the wrding and pictures (if any) will nt be changed. In shrt, yu will hae seen all the free respnse prblems n the test prir t taking the test if yu study what is recmmended. Yu will be assigned t a partner ahead f time and if yu chse t d s, yu may cllabrate and cperate t write yur perfect slutin during the Final. Each persn in the pair will be required t turn-in their wn slutins t the single prblem. Yu will be gien a clean equatin sheet t use during the exam s that eeryne has equal resurces. Generally, pints fr each free respnse prblem will be awarded fr the fllwing: Clear diagram r free bdy diagram with all gien data indicated Writing the crrect equatin(s) t be used in slutin Crrect mathematical manipulatins and algebraic substitutins A clearly bxed crrect answer with crrect units A cmplete sentence explaining yur resultant numerical answer

2 LAHS PHYSICS SEMESTER FINAL EQUATIONS sin ø = pp/hyp cs ø = adj/hyp tan ø = pp/adj a + b = c x = a = t t x x = t at = = + at + a(x x ) x x = x x t + = ( at + )t a = -g g = 9.8 m/s x x y = x t = ( cs θ )t = ( sin θ ) g(y y ) y y = ( sin θ y )t gt = sin θ gt F = ma W = mg fs µ sn fk = µ kn πr = t a c = r F c m = r F = G m m r G = 6.67x0 Nm kg Mn mass = 7.35x0 kg Earth mass = 5.98x0 4 kg Sun mass =.99x0 30 kg Mn radius =.74x0 6 m Equatrial Earth radius = 6.37x0 6 m Sun radius = 6.95x0 8 m Distance frm center f Sun t center f Earth =.5x0 m Distance frm center f Mn t center f Earth = 3.85x0 8 m W = Fdcs θ W net = KE K = m PE = mgh P = W t

3 Semester Final Reiew Prblems Kinematics. Plice detecties, examining the scene f a reckless driing incident, measure the skid marks f a car, which came t a stp just befre clliding int a Wal-Mart t be 50 meters. It is knwn that the cefficient f kinetic frictin µ k = 0.89 between the specific brand f rubber tires n the car and the rad. The speed limit in the area is 0 m/s (abut 45 mph). Assume the skid marks are straight and use Newtn s laws and -D kinematics t determine if the drier f the skidding car was speeding befre she began skidding?. A medical relief airplane climbs t an altitude f 00 m and flies at a cnstant cruising elcity f 80 m/s. The cpilt steps t the back f the plane and pens the carg dr. She wants t drp a medical supply package t a landing site at a remte illage. a. Neglecting air resistance, use -D kinematics t determine hw far (hrizntally) befre the plane flies er the illage must the package be drpped? b. T preent the 5 kg supply package frm getting damaged, the illagers set up an airbag at the landing site. The airbag is capable f stpping the supply package in 0.4 s and stands 5 meters abe the grund. Use kinematics t determine the elcity f the package just befre it hits the airbag. 00 m Range Airbag 3. A skydier jumps ut f a helicpter hering at 500 m abe the grund. She free falls fr 5 secnds befre pening her parachute. Assume the parachute pens instantly and allws her t trael at a cnstant elcity f m/s dwnwards until she reaches the grund. a. Hw much distance des she cer during the initial free fall? b. Hw much time des it take her t reach the grund? c. At the same time she jumps frm the helicpter, her she cmes ff. Hw much time des it take her free falling she t hit the grund assuming n air frictin? d. What wuld the final elcity f the she be just befre it hits the grund? 4. Cnsider a prjectile with an initial elcity ectr f 34 5 abe the +x-axis. The prjectile is sht frm grund leel n a planet different than Earth where the acceleratin f graity isn t knwn. The Range f this prjectile is 80 m and it cmes t rest at the same leel at which it was sht: y = y f = 0 meters. Use kinematics t sle the fllwing: a. Calculate the hang-time f the prjectile. b. Calculate the acceleratin f graity n this planet. c. If the planet's radius was the same as the Earth's, what des the result in part B imply abut the mass f the planet?

4 5. An archer shts an arrw frm the tp f a building at a speed f 8 m/s. The building is 40 meters tall. Ignring air resistance, find the speed with which the arrw strikes the grund when the arrw is fired (a) hrizntally (b) ertically straight up, and (c) ertically straight dwn. Yu must use kinematics and the quadratic frmula t sle this prblem. 6. An LAHS quarterback just abut at the sideline and is 0 meters (r abut yards) frm the gal line pyln (range marker at the gal line) that is in frnt f him. He thrws the line drie ball with a elcity f 4 m/s at an initial angle f 0 abe the hrizntal. His receier runs at a cnstant speed 6 m/s fllwing the gal line starting 6 meters (abut 6.6 yards) away frm the pyln at the same time the quarterback releases the ball tward the pyln. Assuming nne interferes with the play, the receier is essentially a pint mass and if caught, the ball is caught at the same height that quarterback thrws the ball, determine if the receier reaches ball in time t catch it at the pyln. Newtn s Laws Prblems 7. Cnsider a 65 kg clwn with an initial elcity f 0.0 m/s sliding up a rugh circus slide inclined 38 abe the hrizntal and measuring 6.5 m alng the diagnal. The cefficient f frictin between the slide and the clwn is µ k = 0.5. Use Newtn s laws f mtin t predict the highest pint the clwn will slide t. θ µ k h 8. A kinetic artist wants t build a life size duble mass system in equilibrium, n an incline plane. The initial design cnsists f m = 35.0 kg cnnected t m = 7.5 kg by a thin, cable wrapped er a pulley. The artist hires yu t predict the exact angle at which the system will maintain static equilibrium withut any help frm frictin. Use Newtn s laws t crrectly calculate the angle that maintains static equilibrium and get paid $750. m θ 9. Earlier this mrning I saw Ms. Satterwhite, massing in at a liberal 8 kg, skate barding thrugh the quad. Suddenly, she flipped his bard upside-dwn and skidded the wden bard scraping alng the cncrete fr 4. m then stpped. If the cefficient f kinetic frictin between the skatebard and the cncrete quad is 0.73, use Newtn s laws t predict the skidding skatebard s initial elcity just befre it began t skid. m 0. A physics student is wants t be stuck t the interir wall f an amusement park ride called the ROTOR. If the radius f the rtating cylinder is 4. m and the cefficient f static frictin between the student and the rtr s inner wall is 0.56, predict the minimum safe speed at which the Rtr s flr can be remed withut the student sliding dwn the wall. R

5 . A mdel airplane is tied t a string and prpelled by a small electric mtr in a perfect hrizntal circle with a circumference f 3 m at cnstant speed. The plane isn t really flying. Predict the time it takes fr the plane t cmplete ne cmplete relutin. 5 r. Cnsider a circus clwn weighing 70 N. The cefficient f static frictin between the clwn s feet and the grund is She pulls ertically dwnward n a rpe that passes arund three frictinless pulleys and then tied arund her feet. What is the minimum pulling frce that the clwn must exert t yank her feet ut frm under herself? Graity and Energy Prblems 3. Assuming yu are at the equatr and yur mass is 68 Kg, will yu weigh mre when the mn is n yur side f the earth r when the mn is n the far side f the earth? Hw much mre (in Newtns)? (Assume the mn, earth and yu are in a straight line in each case.) G = x 0 - Nm /kg Equatrial radius f earth = 6.38 x 0 6 m Mean radius f mn =.74 x 0 6 m Mass f earth = 5.98 x 0 4 kg Mass f mn = 7.35 x 0 kg Mean distance between the mn s center and the earth s center = 3.85 x 0 8 m 4. A space traeler whse mass is 90kg leaes earth. What are his weight and mass (a) n earth and (b) in interplanetary space where there are n nearby planetary bjects? 5. Synchrnus cmmunicatins satellites are placed in a circular rbit that is 3.59 x 0 7 m abe the surface f the earth. What is the magnitude f the acceleratin due t graity at this distance? 6. Yur mass is 70 kg and yu weigh 46.5 N mre n planet Atrdx than n planet Xenr. Bth planets hae the same radius f.33 x 0 7 m. What is the difference M A M X in the masses f these planets? 7. If yur weight has decreased by half, what is yur altitude abe the earth s surface? 8. A mtrcycle is trying t leap acrss a canyn. Using the principle f Wrk-Energy Therem, NOT Newtn s Laws r Kinematics, t find the speed with which the cycle will strike the grund n the ther side. The cycle takes ff hrizntally frm a cliff n ne side f the canyn at a speed f 40 m/s and at a height f 75 m. The cycle lands at a height f 50 m. Neglect air resistance.

6 9. A fighter jet is launched frm an aircraft carrier with the aid f its wn engines and a steampwered catapult. The thrust f its engines is.3 x 0 5 N. In being launched frm rest it mes thrugh a distance f 87 m and has a kinetic energy f 4.5 x 0 7 J at lift-ff. What is the wrk dne n the jet by the catapult? If the mass f the jet is 00,000 kg, what is its elcity? 0. An archer shts an arrw frm the tp f a building at a speed f 8 m/s. The building is 40 m tall. Ignring air resistance, find the speed with which the arrw strikes the grund when the arrw is fires (a) hrizntally (b) ertically straight up, and (c) ertically straight dwn. Yu must use the Wrk-Energy Therem, NOT Newtn s Laws r Kinematics.. The President, upn learning f his ictry in the recent electin, threw the 0.75 kg mug he was hlding at the time straight up int the air with an initial speed f 8.0 m/s. (a) Hw high wuld it g if there was n air frictin? (b) If the mug rises t a maximum height f nly.8 m, determine the magnitude f the aerage frce due t air resistance. Yu must use the Wrk-Energy Therem, NOT Newtn s Laws r Kinematics. Answers: (Yu shuld duble check with at least 3 ther students t because these answers were gien by students and may nt necessarily be crrect.) m/s. a) 5 m b) 0 m/s 3. a) 0.5 m b) 07 s c).58 s d) m/s 4. a) 5.8 s b) 4.9 m/s c) half mass f Earth 5. all same 39.6 m/s 6. N m degrees m/s m/s..99 s. 34 N N 4. a) 90 kg, 88 N b) 90 kg, 0 N m/s 6..76x0 4 kg 7..64x0 6 m m/s m/s,.5x0 7 J m/s all same. a) 6.5 m b).95 N