# Answer Key

## Transcription

Answer Key

Velocity Answers 1. Name md velocrty do not ha!e the sme meaning to scientists. Spee,l ts a sutltr tluun /irf. wfilcll mcans it can be completely described byitsmagnitude(orsize)'Ihâ‚¬lnagnitudeisgiuenbyanunrberandaunit Forcxample.anoblecr'sspeedmaybemeasuredasl5 meteLs pet second Speed An airplane llies 525 kilorneters north in 1.25 hours. what is lhe airplane's vetocit-v? i.ooLrngror l_\"f!uqitf Given rl=525 Krn \OR --- l'll: t = 1,25 h ;;; ait -- r,__-..-,-_.-____:-.,-- -- I sorution . S25 Knr \()R t rr/ t.ZS h I * 42t) Klt/h NOIII H I r-L rcclor r/uqt1li\ ln arder lo measure a lecior quantity, you must know the both its rnagnitude and tiirection. I he velocity object is detetrnined by nrasuring both the speed and ditec'li(r? in which an object is traveling. Velocity is a ofe . tfthe speed ofm 2. object chuges, thcn its relocity also chmges. . tfthe direction r A chmete in either speed, direction, or both causes a oharge in relocity in rthich 3. l: What is the velocity of a I A cruise ship travels south I car that travels 100.0 meters. northeast it) 4.65 seconds? ihisclistanceif i ts 0.305 east across a river at 19.0 meters per minute. Iong does it take for the ship to reach rhe other 4 I Asoccerplayerkicksaball 6.5meters. I{owmuchtinreisneededtbrtheballtotravel velocity is 22 meters per second, m object is lraaelin!! changes, thcn its velocity changes You can use r r/ I to solte velocity problems in the same moner that you changed the fo.m ofthe equation to solve speed problems in I'art A. The boldfaced v is rned to represant \elocity as a vector quantity. l he la'iables d and t re ured for distuce ad time. The velocitJ- ofen object ir motion is equal to the dirtancâ‚¬ it tr&vels per unit oltine in e givetr dircction. Iixample Reratioushif side? 223.68 lfthe river m is 4,250 tneters lvide, hoiv in Joaquin mows the lawn at his grandmother's home duriog the summer months. Joaquin measured the distance across his grandmother's lawn as I 1..5 meters a lf.Ioaquinmolvsonelengthacrosslhelawnt'romeasttowestinT.l0seconds,thenwhatislhevelocitv of the lawnrnorver? 1.62 m/s WEST ofthe lawn, Joaquin turns the larvnmower around. [{e morvs in the opposite direction but maintains the same speed. what is the velocity of the lawnmower'.) I .62 m/s EAST b. Once he reaches the edge A family drives 88 1 miles from floustoo. T ex&s to Santa Fe. Nerv Mexico for vacation. How Iong will take lhe farnily to reach their destiuation ifthey travel at a velocit-v of55.0 miles per hour, northwesl? it 16.02 h A shopping cart is pushed I 5.6 shopping 7. Exnmple 2: A boat travels witb a velocity equal to I 4.0 meters per second, in meters does the boat travel? east in 5. I What is the vetocity of rhe tennis b. lfthe tennls ball travels l,ooking for distrmci 'I'ime '. 5. 14.0 meters per second. east l5 seconds distance Rclationshlp 4.52rn/s SOUTH at constant speed, what is its velocity when l.iam retums Katie's serve? 4.S2ru/s A driver realizes lhat she is traveling in the wrong direction on a one-rvay street. She has already driven 3.5 meters at a velocity of I 6 meters per second. east before deoiding to make a lJ-turn. How long did it take fbr 14!m x5.15s=?31m = v x, - the driver to realize her Given .= balt? ]\OR"TH Solution Distance the boat travels Velocity ofthe Katie and her best friend l,iam play tennis every Saturday nrorning. When Katie serves the ball to Lialn, it travels 9.5 lneters south in 2. I seconds. a. 5 seconds, What distance meters west across a parking lo1 in 5.2 seconds. What is the velocilv cart? 3 m/s WEST 'l'he boat travels 72. I meters. error? 0.22 S 'luan's ntother drives I 2.5 miles southwest 10 her favorite shopping mall. What is the velocity ol her automobile if she anives at lhe mall in 7.25 minutes? 1.72 mil rnin SW l0Abusistravelingat79.7kilonrelersperhoureast,howt'ardoesthebustravel = vx! 1 I l. A girl scout troop hiked 5.8 kilometers southeast in l.-i hours. What L4.5hours? I15.57Km ivas the troop's velocity'l J,87Km/h SIi 2. A volcanologisl noted that a lahar rushed dorvn a mountain at 32.2 kilometers per hour, south. IIow far did the mud l]ow in 17.5 minutes? 9.39 Km Acceleration Worksheet. a highway a driver slorvs liom ?4 m/s to 15 m/s in l2 seconds. \\'hat is tlle automohile's acceleration? (Reurembcr that a negative value indicates a slowing down tr deceleration.) \Vhile traveling aloug Name: Date: -0.75m/s/s 14.2 Acceleration A parachute Acceleration is the rate ofchange in the speed ofan object.'l'o detennine the rale oFacceleration, you use the formula below. 'Ihe units lirr acceleration are metels per second pet secontl or m,/s2. Arcel':ration - o1l fl raciilg dragster opens and changes tlre speed ofthe car frorn 85 m,/s tal 45 m/s in a period 0f4.5 seconds. What is the acceleratiorl ofthe dragster? -tt.9 m/slS The table belo\ry includes data lbr a ball rolling down a trill, Fill in the lnissing data values in the tablc aud delentrire the acceleratioo ofthe rolling ball. Final speed-Beginning speed Time 11-Yr A positive value for acceleration sltorvs speeding up, and negalive value fbr acceleration shorvs slowing down Slowing down is also called deceleration. I'he acceleration tbnnula oan be rearranged to solve for other variables such .. as linal speed (v:) and time (/). l/-v.1 -.. )r-llr a Acceleralion EXAMPLf,S L Askaterincreaseshervelocityfiom2.0misto10.0m/sin3.0seconds.Whatistheskater'sacceleration? Solution lf'a car can l l were 50 l .. Arcetefallon 100m,'s-20rn./s = 2!n'.is. ?s 'fhe acceleration ofthe skater is 2.7 meters pel second l!!llc9-'r-]:ll.. :ls"ggltgj ] ttetationship A ir complete stop. l{ow much time will it 8.0 seconds, what tvould be its final speed afrer 5.0 seconds cart rolling dowr an incline for 5.0 secr:nds has an acceleration of4.0 nr/s2. ilits starting speed Ifthe of2.0 cart has a beginning speeii 22 m/s A helicoptel"s speed increases lronr 25 I m1s to 60 n/s in 5 seconds. What is the acceleration ofthis helicopter? 7 mlsl$ l Assheciimbsahill.aLJ,clistslowsdownfronr25ni/hrto6miflrrinl0seconds.Whatisherdeceleration? I A car accelerates itt a rate o[3.0 m/s2. to reach a final speed oi25.0 rnJs? go fronl 0 t0 60 mi/lu a I I v2*Yt 2. "--_ ,__- rni/lrr? {i7.5 milh m/s, what is its t'inal speedt I per second. -!-5 nlsls A car traveling ai a speed o{'30.0 l,r/s encouilters an energencv and oonres to take for the car to stop ifil decelerates at -4.0 trl/s';? 7.5$ lfits original speed is 8.0 m/s, how many secorrtls will it tale the car A motorcycle traveling at 25 nrotorcycle? Solution -lrmi=-=)ir:5Dm/s-80m./s 3 0 m!s" -l'he time lor the car to reach its tinal speed is 5.7 *1.9 mi/h/s l0 A car starting from rn,is accelerates at a rate of7.0 m/s: Iix 6.0 seconds. what is the final speetl ofthe 67 m/s rest accelerates at a rate of8.0 m,/s/s. Whot is its tlnal speed at the end of4.0 seconds? 32 mls II After traveling for 6.0 seconds, a nrnner reaches a speed of l0 m/s. What is the runner's acceleration? 1.61 m/s/s seconds t2. A cvclist accelerates at 13. a rate of7.0 rn,/s2. How long will it teke the cyclist kr reach a speetl of 18 A skateboarder traveling at 7.0 lneters per second rolls to skateboardor'sacceleration? -2.33 m/s/s a stop at the mis? 2.57 top ofa raulp in 3.0 seconds. Whal ,s tl)e