Suppose that an object travels from one point in space to another. Makz m5f;uytm n/*e a comparisoumm; /z*n5 ftyn between the displacement and the distance traveled.

  When is the average velocity q4vp:g -m s5 ouwh 5xe4lbh 49(baj3xcof an object equal to the instantaneous velocity?

  A new car manufacturer advertises that their car can go "from zero to sixu )q 2ip 2/5tfxgrx8qwty in 8 s". This iwq2x8ru xf /p2t 5)iqgs a description of

  An object moving in the +x axis experiences an acceleration of i+ j42fk gcfy-$2.0 \; m/s^2$. This means the object is

  Suppose that a car traveling to the East (+x direction) begin,gd0tol,j 3 .ii sql1gs to slow down as it approaches a traffic light. Make a statement concerning it,og d1 jq,tlslii.g 30s acceleration.

  Suppose that a car tr-gpndonh+8v 4aveling to the West (-x direction) begins to slow down as it approaches a traffic light. Make a statement concerninnhpd gvo8n+4 -g its acceleration.

  Suppose that an object is moving with a constant vel kbq 88c*)/ qzuxk2kmwocity. Make a statement concerning its acceleratiz/m*kx8 uwk q)bkqc2 8on.

  If the velocity of an objectxddtz24 4)h+feqrmab0 oai zn- ay(p71d2 n* k is zero, does it mean that the acceleration is zeroobnx*mdthezr+dpqaa1f4z 2 )na(07k 2 y-d4i? Support your answer with an example.

  Can an object's velocity change direction when its acceleration is constant?kze3c im8 3:nq Suppz: 8k3 eqni3mcort your answer with an example.

  Suppose that an object is moving with constant acceleratqb 0kv /0ltlmy(b j*a6ion. Make a statement concerning i vayb/*tl0( mj 6lqkb0ts motion with respect to time.

  Can an object have incre v7ngm18y pg)4g5pxe (hz 4fabasing speed while its acceleration is decreasing? Support your a agg(vgxnp5f 4ez mp8h471 )ybnswer with an example.

  Suppose a can, after an initial kick, moves up along a smoothythb/jvg,u1. ( 0t n)heol; - (dazjfm hill of ice. Make a stat ).( uadhvtjbl nyg(eto,1;0jfhzm /-ement concerning its acceleration.

  Under what condition is average velocity equa6m8t:owpc:s sl to the average of the object's initial and p sc86w:tmso:final velocity?

  Objects A and B both start at rest. They bobhn-i*az a)ivhne2m)+eqx: - th accelerate at the same rate. However, object A accelerates for twice thi:zn)xim-) hb*n ve-aqa e+ h2e time as object B. What is the final speed of object A compared to that of object B?

  Objects A and B both start from rest. They both acceleratk lwzf /6u:of8e at the same rate. However, object A accelerates for twice the time as object B. What is the distance traveled by o/fku f6w8zo l:bject A compared to that of object B?

  When an object is released from rest and falls in the absend,d6in+(u yu q*;v 7gg0c yk++wupuf ece of friction, which of the following is true condguv+nq( g + p ;yikf*7w60yd eu,u+uccerning its motion?

  When an object is releasm j30q8r p7vtb6rwny6g82xfled from rest and falls in the absence of friction, which of the follox68j7 gqt0bvpr6 y lrf23nwm8wing is true concerning its motion?

  Suppose a ball is thrown straight up. Make a lltv1x3 z j65z/cx-dl statement about the velocity and the acceleration when the ball reaches the highe3l5x l1j/tlzvzd6 xc-st point.

  Suppose a ball is thrown straight up. Wx(4dd) hk.bzk hat is its acceleration just before it reac hxkk4( db.)zdhes its highest point?

  Suppose a ball is thrown strai 0,fc0tc ud6vlght up, reaches a maximum height, then falls to its initial height. Make a statement about the di,vltfd0cu06 crection of the velocity and acceleration as the ball is going up.

  A ball is thrown straight up, reaches a maximum height, thomt5(w.mw3m-mz3:f *yb sxdk l( q 1kjen falls to its initial height. Make a statement about the direction of the velocity and acceleration as the ball is coming dmz . mwo tb3 wq*sfkkl35(:(1xym jd-mown.

  Suppose a ball is thrown downw2:vq5,/ grugvoio 8moard in the absence of air resistance. Make a statemen/m gv r2,5vooq:oi8gu t concerning its acceleration.

  Suppose a skydiver jumps from a high-flying plane. What is her acceleration w0kh7m7mmpg8kn0 44liu ky9 thhen skmu9phklig 8mm4 k0 7htyn704he she reaches terminal velocity?

  A ball is thrown vertically upward with a speed v. s)8s4n2 t e8y5/omr o xijpmq* An identical second ball is thrown upward with a speed 2v (twi*8 nsjmsri2potm 4yxo58 /eq) ce as fast). What is the ratio of the maximum height of the second ball to that of the first ball? (How many times higher does the second ball go than the first ball?)

  Ball A is dropped from romtg*cbb,88 x9b/m rrj-ov)the top of a building. One second later, ball B is dropped from the same building. As time progresses, the distan jmo8b9r-8b,/rctbm*g rov x) ce between them

  Ball A is dropped from the top of a building. One secondxz. dypoao:kz6 ldce6 k; *0:qr39njn later, ball B is dropped from the same building. As :0: 6p ddn;aock9 key6r*3zjx lqon.z time progresses, the difference in their speeds

  Two objects are thrown from the0m7py8sc, fn1b )cuad top of a tall building. One is thrown up, and the other is thrown down, both with the same initial speed. What are their speeds 08up7)dcyf ,cbn s a1mwhen they hit the street?

  A brick is dropped from the top of a buildingbfr9g1tq70c-h wfbr -. A second brick is thrown straight down from the same building. They are released at the same time. Neglect air resistance. Compare the acceleratib9t rqgw7 rbhff0-c- 1ons of the two bricks.

  An object is moving with constant non-zero velocity ft c r-orc /9(f(e+qwdin the +x axis. The position ed/or r(tffq wc(+ c9-versus time graph of this object is

  An object is moving with constant non-zero aceh j9d,k63o hpceleration in the +x axis. The position versus time graph of this objecehd6koj h,3p9t is

  An object is moving with constant non-zero velocity in the +7+p,unec 1srh x axis. The velocity versus time graph of this object np ,ru s7ec1+his

  An object is moving with constant non-z. +lf yswp4t;mero acceleration in the +x axis. The velocity versus time graph of this obj;p wl+ms.fy4 tect is

  The slope of a position 1,fg q;jr;w8 hd 0ydcqversus time graph gives

  The slope of a velocity a(knv(o-3 bivversus time graph gives

  The area under a curp0g c49juxlir5b d*8vve in an acceleration versus time graph gives

  The area under a curve in a ve / 3y vkw 8ro876xy8vrmth0ua kgwv;+elocity versus time graph gives

  If the position versus time graph of an object is a horizontalas ln+e(h)xv8kmoque +b862 y line, the object (8bkeovenh26qu) a s+xy8lm+is

  If the position versus time graph of an object is a verticalw2im4n w:rc xvmh,8m9 line, the object is9w wrh , :nmvm2xc4m8i

  If the velocity versus time graph of an osj e30wr1 o(dcbject is a horizontal line, the object isjc 13( d0rsewo

  If the velocity versus time graph of an object is a straight line mak5c(;nw kffx )iu5j1 w iqh9-zbing an angle -u )qhw;5xc(w5i9 zf jb1kifn of 30 degrees with the time axis, the object is

  An object moves 15.0 m north and then 11.0 m south. Find bot;sec ln64uv krd.s87ahy p qo/wan uet0562 (eh the distance traveled and the magnitude ofuu/wathks6vo(le 7 0q6;25e dnr acp 84yn.es the displacement vector.

  A boat can move at 30 km/h in still water. How lonyibbahw. 3)xdb5d9 bel zy(52 g will it take to move 12 km upstrea( yi.be 9z dw355bhay2l)xbbdm in a river flowing 6.0 km/h?

  55 mi/h is how many m/s? (1 mi = 160xa7ew t:-qwszz) h /pa.z,/gx9 m)

  What must be your average speed in order to travelg98a yvv. * k6unwlk-g 350 km in 5.15 h?

  A runner ran the marathon (approximately 42.0 km) in 2 hours and 57 min. i :udpry ,2mo85u4iyy What is the average sd8,i 4pr: m2oyy5iuuypeed of the runner in m/s?

  A car travels 90 km/h. How lo)(9rxxi utfc9n*zo/ ec:f4s vng does it take for it to travel 400 km?

  A ly (light year) is the distance that light travels in one4x(ij6nm d1v ,oree1j year. The speed of light is 6ireoj4vd n(,xe1 mj1 $3.00 \times 10^8 \; m/s$. How many miles are there in a light year? (1 mi = 1609 m, 1 yr = 365 d.)

  If you are driving 72 km/h along a straight road and you look ttkyy8s61zk4hp(d,nw ff ;,*vgt*at5r*wck to the side for 4.0 s, how far do you trav4;h8d at ,**fw 5k1 fr(cysvk,tytwk*6nztp gel during this inattentive period?

  If you run a complete loop around an kv:yh;1cwy4m ja/ q/ ,zqf1 lxoutdoor track (400 m), in 100 s, your average velocita q1 ,jkczh/:w; yymq 1l/v4xfy is

  A polar bear starts at the North Pole. It travels 1.0 km south, e h6lcyy/5dvlv/ h5kv36 y*afthen 1.0 km east, then 1.0 km north, then 1.0 km west to retur a6eyfhh5dv *53k/l/lvy6 ycvn to its starting point. This trip takes 45 min. What was the bear's average speed?

  A polar bear starts at the North Pole. I81ij/2 ,r l8bmsbxav pt travels 1.0 km south, then 1.0 km east, then 1.0 km north, then 1.0 km west to return to itspb8var/1ls8 im2 ,bxj starting point. This trip takes 45 min. What was the bear's average velocity?

  You are driving home on a weekend fruf24meza,vt7 ,c p8f wom school at 55 mi/h for 110 miles. It then starts to snow and you slow to 35 mi/h. You arrive home after driving 4 hoursa z ,p82wtcvef u4m,7f and 15 minutes. How far is your hometown from school?

  A motorist travels 160 km7 qq7exnk sc/3ii94+a* edrw e at 80 km/h and 160 km at 100 km/h. What is the average speed of the motorist for th sn/iq 97eiedk7ewx+ 4aq*c r3is trip?

  A motorist travels for 3.0 h at 80 km/h and 2+*wg dyj6l rg*.0 h at 100 km/h. What is her averyl6r*+*ggwd jage speed for the trip?

  An airplane travels at 300 mi/h south for 2.00 h and l.z66wp/oq t athen at 250 mi/h north for 750 miles. What is the average q6ot w6lpz/a.speed for the trip?

  In a 400-m relay race the anchorman (the person who runs the lfpr fn.w a8-;vast 100 m) for team A can run 100 m in 9.8 s. His rival, the anchorman for team B, can coverf;w8p -anfrv. 100 m in 10.1 s. What is the largest lead the team B runner can have when the team A runner starts the final leg of the race, in order that the team A runner not lose the race?

  A car decelerates uniformly and comes to 9o br ,y:b7 9vu bbij.vce-pc./xdma)a stop after 11 s. The car's average velocity during deceleration was 76 km/h. What was the car's deceleraij9r.pud: c/bxea, 7yv vm 9ob-)bb.ction while slowing down?

  An airplane increases its speed from 100 m/s to 160 m/ hct+ )2(g:)nln wwmsls, at the average rate of + )n w)2wmct(s h:glln$15 \; m/s^2$. How much time does it take for the complete increase in speed?

  A car traveling 60 km21nzmpvmw4b2qp e:;r/h accelerates at the rate of $2.0 \; m/s^2$. How much time is required for the car to reach a speed of 90 km/h?

  A cart starts from rest and accelerates acrrhoy4 iu0;5 t $4.0 \; m/s^2$ for 5.0 s, then maintain that velocity for 10 s, and then decelerates at the rate of $2.0 \; m/s^2$ for 4.0 s. What is the final speed of the car?

  A car travels at 15 m/s for 10 s. It then speeds up wignr*ts), 3e29p8np cc9 xmxaqnr t4t6th a constant acceleration o9 r*3 s6tg8xpnx9tcpqrmn tce,n2a)4 f $2.0 \; m/s^2$ for 15 s. At the end of this time, what is its velocity?

  A cart with an initial velocity of 1.8 m/s experiences a constant acceleratimx gth; nhomr2n6i 6jd-*/u5xon of omuhr6x-mx*ig5hn;nd 62/t j $3.2 \; m/s^2$. What is the cart's displacement during the first 4.7 s of its motion?

  A bullet moving horizontally to the right (+x direction) with a speed of 24.k.03atkfqnb lq0r *a8 m/s strikes a sandbag and penetrates a distance of 55.06 cm. What is the average a0b*a .3lat.qnqrk f k0cceleration, in $m/s^2$, of the bullet?

  A jet fighter plane is launcrup30 yn, ;3z xkjwpf3hed from a catapult on an aircraft carrier. It reaches a speed of 42 m/s at the end of the catapu3kwz,3ryu;fjnp 0 p x3lt, and this requires 2.0 s. Assuming the acceleration is constant, what is the length of the catapult?

  A car starting from rest moves with constanl0x rmmv+y/o -t acceleration of $2.0 \; m/s^2$ for 10 s, then travels with constant speed for another 10 s, and then finally slows to a stop with constant acceleration of
-$2.0 \; m/s^2$. How far does it travel?

  A car goes from 40 m/s to 80 m/s in a distance of 200 m. What is its vzsr0e(b xz75xj 2(dnk ig+e5average ac(edg5ez(n kr5jsb2z7+ iv 0x xceleration?

  An object starts from rest and undergoes uniform acceleration. During the firsxactbj:z( + )k2aveyt us8;i hs+w0/ xt second it travels 1.0 m. H:;e ca2)+s8k y+su(hxaivb xtw/tjz0ow far will it travel during the third second?

  An object is moving in a straigle xw n3.c dc.k5ndk+4ht line with constant acceleration. Initially it is traveling at 16 m/s. Three seconds later it is traveling at 10 m/s. How far does it move during this tc. d3.5encd4w+xnlk k ime?

  A car starts from rest and avom* t :g )pym(zy-zg4ccelerates uniformly at $3.0 \; m/s^2$. A second car starts from rest 6.0 s later at the same point and accelerates uniformly at $5.0 \; m/s^2$. How long does it take the second car to overtake the first car?

  A car with good tires on a dry road can decelerate at abouq ,xen mtbjp:q)cp0)rw q )2tanc (46ut $5.0 \; m/s^2$ when braking. Suppose a car is initially traveling at 55 mi/h.
(a.) How much time does it take the car to stop?    $s$ (only input numerical values)
(b.) What is the stopping distance?    $m$ ((only input numerical values)

  At the instant a traffic light turns green, a car that h(zh3cf e g0r0uas been waiting at the intersection starts ahead with a constant c0 zghf3ue 0r(acceleration of $2.00 \; m/s^2$. At that moment a truck traveling with a constant velocity of 15.0 m/s overtakes and passes the car.
(a.) Calculate the time necessary for the car to reach the truck.    $s$ (only fill in numerical values)
(b.) Calculate the distance beyond the traffic light that the car will pass the truck.    $m$ (only fill in numerical values)
(c.) Determine the speed of the car when it passes the truck.    $m/s$ (only fill in numerical values)

  An object is thrown upward with a speed oat3sp -t2gc2bf 12 m/s on the surface of planet X where the acceleration due to 2sbc3 t2a-pg tgravity is $1.5 \; m/s^2$. What is the maximum height reached by the object?

  An object is thrown upward with a speed of 12 m.1u(k:. i2 amyh iap*sy0 cfbo/s on the surface of planet X where the acceleration duec0ak um.:hifyy(p o i.1sab*2 to gravity is $1.5 \; m/s^2$. How long does it take for the object to reach the maximum height?

  An object is thrown upward with a speed u1bnrqtq p*:tnu x+6 /of 15 m/s on the surface of planet X where the acceleration due6btrun q tqpx+n*1 /:u to gravity is $2.5 \; m/s^2$. How long does it take for the object to return to where it is thrown?

  An object is thrown upward with a speed of 14 m/s on the su;lk(nsiu taz*w/ 0hb )rface of planet X where the a/ bi(t )swhka;l *u0nzcceleration due to gravity is $3.5 \; m/s^2$. What is the speed of the object after 8.0 s?

  Human reaction time is ): tg: jk4n. gby8u1uajjlx7ausually greater than 0.10 s. If your friend holds a ruler between yo:k gj)la8jaug74jxb.:t yn 1 uur fingers and releases it without warning, how far can you expect the ruler to fall before you catch it?

  A ball is thrown upward at a velocity of 19.6 m/s. What is its ,z )b4 :lsinuxvelocity after 3.004unzb, i): xls s?

  A bullet shot straight up returns to its starting point in 6 s. What is th4xi flt*c 3ocs *j+lf2nsu6 tj+:*wuee initial sp6+ to i*fc ujw3*f*s4j:tcn l2+eluxseed of the bullet?

  A ball is thrown straight up with a speed of 36.0 m/s. How long d 1pekm)4y p( uj,11lma)rdpe noes it take to return to its sta)k(pp l ,nme4mey 1djr)1 u1parting point?

  A ball is thrown downward from the top of a building with an initial speed of 134r2 1ufej(lh cz+2 vnl m/s. It strikes th2vl1 e nlcr4u(2fjz+he ground after 2.1 s. How high is the building?

  A ball is thrown stra4pv4xulq*htovqd20vp x/.hm o (x4 v1ight up with a speed of 30 m/s. (only fill in numerical value in tqp2pv th 4vl 0oq. dxvmxo41xuv 4/(*hhe blanks)
(a.) How long does it take the ball to reach the maximum height?    $s$
(b.) What is the maximum height reached by the ball?    $m$
(c.) What is its speed after 4.2 s?    $m/s$

  A foul ball is hit straight up into the air with a s s qqqxfcq08:9zr 2e7z8+vqiepeed of 23.9 m/s. (use $g=10 \; m/s^2$, only fill in numerical value in the blank)
(a.) Calculate the time required for the ball to rise to its maximum height.  (数值)  $s$
(b.) Calculate the time for the ball to fall back to the height at which it was hit.  (数值)  $s$
(c.) Calculate the maximum height reached by the ball.  (数值)  $m$
(d.) Calculate the ball's speed 2 seconds later.  (数值)  $m/s$
(e.) Determine the time at which the ball pass a point 11 m above the point of contact between the bat and ball for the first time.  (数值)  $s$
(f.) Determine the time at which the ball pass a point 11.0 m above the point of contact a second time.  (数值)  $s$

  In Fig. below, what is the velocity at t = 1.0 /so9i z:j-j 6 tsd;eh0cih mp8s?

  In Fig. below, what is the vel(b a :f94rxgqoocity at t = 2.5 s?

  In Fig. below, what is the velocity at t = 4.0 s?w:ar5ahhsz31b8* ris 2zk ge6

  In Fig. below, what is the veloffe,pmp 9 1g0+k;k 1yhd3dqvyh0 vff4 city at t = 5.5 s?

  In Fig. below, what is the average vezk)ewaxljsapj)):ie0rp 3 /9locity from 0 to 4.0 s?

  In Fig. below, what is the average velocity from 0 to 6.0 f4i i:f ,0lqj:;cavm vs?

  In Fig. below, what is the accelz+hq99r zygu 3y04(x6hbg eyferation at 1.0 s?

  In Fig. below, what is h)b 7nk-r 01gwkh;jzhb5p s s4the acceleration at 3.0 s?

  In Fig. below, what irwh(; u*9 cojmmf0 x8fcnn33zp 3jn b(s the average acceleration from 0 to 5.0 s?

  In Fig. below, what is the averdv+q - kw6,m2yrci;uhage acceleration from 0 to 8.0 s?

  In Fig. below, what is r/6 .l r6 ignya93pxuj394cxdmapsmc r(*6j pthe displacement from 0 to 8.0 s?

Does a car speedometer measure speed, velocity? {speed|velo psl+sz(0u8o sy o,sf/4 g1z hresca42city}

  An object can have a 5dywylv5oi(5j f *l:0eadq2c varying speed if its velocity is constant.

  The velocity of an object can be negative when its x ;ptamb 23.fsz72o/ zomy8ecacceleration is positive.

  If one object has a greater speed than a second object, the fir-b3udg fb6 (whmo*tns0t z97ist must have a greater acceleration.wm9b0gt3s(6bt-hioz7 *dn u f

  Two cars emerge side by side from a tunnel. Car A is traveling wi0h5(i ywos 4qcth a speed of $60 \; km/h$ and has an acceleration of $40 \; km/h/min$ Car B has a speed of $40 \; km/h$ and has an acceleration of $60 \; km/h/min$ . Can A will pass car B at the instant they come out of the tunnel.

  An object can be increasing in speed as its acceleration decreasy e92v)ukbnr) es.

  A baseball player hits a foul ball straight *+k: rl-meg*b ly wd2kup into the air. It leaves the bat witkg2lk dwl*r +y b:-*meh a speed of $120 \; km/h$. In the absence of air resistance, how fast will the ball be traveling when the catcher catches it?    $km/h$ (please only fill in numerical value in the blank)

  As a freely falling object speeds up, what is happening to itmn ktb1pq (5xy1uf.h9;4bas7ec4 i vws acceleration, how does it change if air friction is9(xbk aui1 451 ht4ymw7pbvc.;f qsne ignored?

  As a freely falling object speeds up, what iqv-s h*kt 2g0yd)vp0d ) pwhu8w9 0vkvs happening to its acceleration, how does it change if air friction CAN NOT0uktp y-0k8 v0ps9g *2)dvvdqhhw v)w be ignored?

  An object that is thrown vertically upward 7-jpsomeo t* .will return to its original position with the same speed as it had injomsot*7- .peitially if air resistance is negligible. If air resistance is appreciable, how will this result be altered?

  An object can have zero velocity and nonzero accelerationrw0r2n(d lfq0 at the same time.

  An object can have nonzero velocity and zero acceleration at the sam1mnok6hf3 r2 sf +gc3de time.

  An elevator moving from d1po (jajde wlj87q9j5y ,c-uthe second floor to the fifth floor making no stops alon-d j7uyojljqj9wc ,p5d (8ea1g the way has zero acceleration all the time.

  A rolling ball moves fron g4kh8taoix9yf7p2)u, xv t;m $x_1=3.3 \mathrm{~cm}$ to $x_2=-6.8 \mathrm{~cm}$ during the time from $t_1=2.7 \mathrm{~s}$ to $t_2=5.5 \mathrm{~s}$. What is its average velocity?  (数值)  $cm/s$ (only fill in numerical value please)

  A particle at $t_1=-2.1 \mathrm{~s}$ is at $x_1=3.1 \mathrm{~cm}$ and at $t_2=3.8 \mathrm{~s}$ is at $x_2=7.9 \mathrm{~cm}$. What is its average velocity?  (数值)  $cm/s$

  A person jogs eight completpd8l-i 0v o0 7ll*pdsfe laps around a quarter-mile ($1 \; mile = 1609 \; m$) track in a total time of 11.3 min. Calculate (a) the average speed  (数值)  $m/s$ and (b) the average velocity    $m/s$

  A horse canters away from its trainer in a straight line, moving 108 b,,h 2dgcdi5,ufsy9nt -k-x dm away in 10.0 s. It then turns abruptly and gallops halfway back in 4.8 ,f,diu2ndg -k,9 yc xh-s5 dbts. Calculate (a) its average speed  (数值)  $m/s$ and (b) its average velocity  (数值)  $m/s$ for the entire trip, using “away from the trainer” as the positive direction.

  A car accelerates fromls.7;m vlboa-: al-hfl) v4g i $12 \; m/s$ to $23 \; m/s$ in 5.2 s. What was its acceleration?  (数值)  $m/s^2$ How far did it travel in this time?  (数值)  $m$ Assume constant acceleration.

  A car slows down from l:1j2cykp 5o pf2jiaa4y0nv 4$20 \; m/s$ to rest in a distance of 60 m. What was its acceleration, assumed constant?  (数值)  $m/s^2$

  A light plane must reach an/tje*p 1kdo1jh6.+ak w-le 10 cismz speed of $26 \; m/s$ for takeoff. How long a runway is needed if the (constant) acceleration is $2.9 \; m/s^2$ ?  (数值)  $m$

  A world-class sprinter can burst out of the blocks to essentiall;x8 jnlw+,io 97vees py top speed about 8w oeni 97xvepl+, sj;$11.1 \; m/s$ in the first 14.0 m of the race. What is the average acceleration of this sprinter?  (数值)  $m/s^2$ and how long does it take her to reach that speed?  (数值)  $s$

  A car slows down uniformkr2b.( x 01v,xgdcg ebap96kz ly from a speed of $18 \; m/s$ to rest in 4.51 s. How far did it travel in that time?  (数值)  $m$

  In coming to a stop, a car leaves skid marks 92 (vfe,+emd7pupp2a h :m long on the highway. Assuming a decelvuep (mp efh a7+2,dp:eration of $7.00 \; m/s^2$, estimate the speed of the car just before braking.    $m/s$

  A car is behind a tr;vgbqknr 3el;hk1 3/ huck going $25 \; m/s$ on the highway. The car’s driver looks for an opportunity to pass, guessing that his car can accelerate at $1.0 \; m/s^2$. He gauges that he has to cover the 20-m length of the truck, plus 10 m clear room at the rear of the truck and 10 m more at the front of it. In the oncoming lane, he sees a car approaching, probably also traveling at $25 \; m/s$. What is the closest distance of the approaching car that he can still sately make the attempt to pass the truck? (without hitting the approaching car).    $m$

  A runner hopes to complete the 10,000-m run in less than 30.0 min. Af rsd8 gl;o uulwqr:z8zrm++s*-g 4md0 ter exactly 27.0 min, there are still 1100 m to go. The runner must then accs mdl-:qsur8glu m* dw+0+r4zr; 8gzoelerate at $0.20 \; m/s^2$ for how many seconds in order to achieve the desired time?    $s$