Suppose that an object travels from one point in space to another*3izmy1qppstvp -4c 1. Make a comparison between the displacement and the distance pys3 i4 v1-zp 1mqpct*traveled.

  When is the average velocity of an objec+7xwnca h3v i)8gng p;t equal to the instantaneous velocity?

  A new car manufacturemcyq 6.94daik r advertises that their car can go "from zero to sixty in 8 s"..6mic 9ay4dk q This is a description of

  An object moving in the +x axis expp(f+ u;/lp8hqlmo +yoeriences an acceleration of $2.0 \; m/s^2$. This means the object is

  Suppose that a car traveling to the 6id-7;r eh9:5gfk o qhzs shp9East (+x direction) begins to slow down as it approaches a traffic light. Maksfg5;s he d7ir:h9p9z6hk -qoe a statement concerning its acceleration.

  Suppose that a car tracr zm t,54x l((+2ndthuzb- xmveling to the West (-x direction) begins to slow down as it approaches a traffic ligmx4c, bd5xtrz(t+ z-( h2nlmuht. Make a statement concerning its acceleration.

  Suppose that an object is moving with a constant velocity. Make a statecvwc5kkdq22 +gnt+ , ement concerning its acg2 dc t+n,2+kqk5cevwceleration.

  If the velocity of an object is zero, does it mean that the acceleration f u ze.j 4:0byrgxw aa67(cx7pis zero? Support your answer with an examp (pfu4bxyazxrj :ce.w770ga 6le.

  Can an object's velocity chanp4z69x8hray h q9xgbi4/o t*nx: fv(dge direction when its acceleration is constant? Support your answer with igxdh b(hx qyx:8anpv9r* o6ft z4 94/an example.

  Suppose that an object is movi4h8gk-ht,-pyp1jtl;w :ul xpng with constant acceleration. Make a statement concerp4y;1,hh-:u8 - wt ptgx kjpllning its motion with respect to time.

  Can an object have increasing speed while its acceleration is dmpp,a aelu:igr.t49t54iv4 v ecreasing? Support your tap54, vl. i4g peia9vu:4tmranswer with an example.

  Suppose a can, after an initial kick, moves h/ 6b u7zzcpy0up along a smooth hill of ice. Make a statement co cbz 6u7y/hp0zncerning its acceleration.

  Under what condition is average i( tuo/ew9w 4evelocity equal to the average of the object's initial and final velociww (9oe4ui/et ty?

  Objects A and B both start aqtpk8/ ls6of(mb.c2 e t rest. They both accelerate at the same rate. However, object A accelerates for twice the time as object B. What is the final speed of object A compared to thatsf/bm6 op 2 eq.tlkc8( of object B?

  Objects A and B both sta5p1 g6kfvzvy+i1* b2 wj7vp zs,.wwylrt from rest. They both accelerate at the same rate. However, object A accelerates for twice,sj + vz6yipv1 2w y.7pgwvw*lbk f51z the time as object B. What is the distance traveled by object A compared to that of object B?

  When an object is released from rest and falls in the absence of4x lv8yaq uq9-;pw6zofg1r f.f:jw j0 friction, which of the foll9rxv owfaz.f -j jfq108l6;ug:qp4 ywowing is true concerning its motion?

  When an object is released from rest and fagwr.:4c.psc6pg*7xhqx n: ;t.z7hpth hff e ;lls in the absence of friction, which of the following is truf:*4rpw.z 6hxqh c.:xs pc;n77.g fethht;gp e concerning its motion?

  Suppose a ball is thrown st ab1( -)e66rsnig b7rbhuml9traight up. Make a statement about the velocity and the acceleration when tb (6ai9l)t r7su1rmb-neb6hg he ball reaches the highest point.

  Suppose a ball is throw6 yt)ouyae 99+ ;;kdiplo e9xcn straight up. What is its acceleration just before it reaches its highel; ox6yoke+9 et )ypu ;dac9i9st point?

  Suppose a ball is thrown straight up, reaches a maximum height, then falls jqfb/n o-: p4pto its initial height. Make p:o /np q4bfj-a statement about the direction of the velocity and acceleration as the ball is going up.

  A ball is thrown straight up, reaches a maximum height, then falls to its7/uj-k:)wh+:n ea. jrm.6 ijbhn o osc initial height. Make a statement about the direction of the velocity and acceleration as the ball is c-ojh/hj7na. usc:i o r.:)wn+k b6 ejmoming down.

  Suppose a ball is thrown downward in thf2g;v l269 ete.jet; 1cizi nq-s xmp4e absence of air resistance. Make a statement conce;cjg. tpq291niv f-4;6i ltse mx2zeerning its acceleration.

  Suppose a skydiver jumps from a high-flying plane. What is her acceleration g19w9 oegbmlf(nxr7 5 when she she reaches terminal veloci7em15gw 9n rolfgxb (9ty?

  A ball is thrown vertically upward with b /2kmzwu-7i nk,;jcv a speed v. An identical second ball is thrown upward with a speed 2v (twice as fast). What is the ratio of the maximum height of the second ball to that of the first ball? (How many times higher-j7b;cwu km2,k /ivzn does the second ball go than the first ball?)

  Ball A is dropped from the top of a building. One second later, ball Br ,t.x ) dg;e2i)4ke cjjr:dtp is dropped fr egc :k; x id)ret,pjtj2)rd.4om the same building. As time progresses, the distance between them

  Ball A is dropped from the top vvz ar9;rt: soa;f2um +gphh( d2ed28of a building. One second later, ball B is dropped from the same building. As time progresses, the difference in thei ;;2fa8e(dt2 hhpa9gzr 2 +s:vrdom uvr speeds

  Two objects are thrown from the top of a tall building:qj/f zer)3ap. One is thrown up, and the other is thrown dojraf eq3:)p/z wn, both with the same initial speed. What are their speeds when they hit the street?

  A brick is dropped from the top of a building. A second brick is thrown str,ejjais26+isn kz:gx *u; u *raight down from the same building. They are released at the same time. Neglect air resistan j+*,ng2uijez:s ski auxr;*6ce. Compare the accelerations of the two bricks.

  An object is moving with consta h lhlv3vy734jnt non-zero velocity in the +x axis. The position versus time graph of tylhj3 37vlvh4 his object is

  An object is moving with constant non-zero acceleration in the +x axid,ok :b/ajma* k5o2ea bjb,e0s. The position vers:ojkdbaam,*e ,eobk2/ a5jb0 us time graph of this object is

  An object is moving wieybk.eku 8j z s wqrd6 t/c5rn6y(7u9(th constant non-zero velocity in the +x axis. The velocity versus time graph of this object isru7ec8zrdjnw u(qb5k 9/ky6s( te y.6

  An object is moving with constant non-ze s,3u qw(c7z, fulbs5aro acceleration in the +x axis. The velo, zuqfcub5,al73ws(scity versus time graph of this object is

  The slope of a position versus time graph3s)a0h8 uhkn5i;bw,k2hcfca gives

  The slope of a velocity versus time grapkz/mgazrbe*q(ei 5z5 9 v8cn 5h gives

  The area under a curve in 5ims1sfp 3ugo8mi:v7 an acceleration versus time graph gives

  The area under a curve in a-7+mskgc3x3cq o )j .z;i4zpjfrw5zm0wn i1h velocity versus time graph gives

  If the position versus time graph ofb1xcsdfwz org 8 k/).1 an object is a horizontal line, the object isco . drf1b1zx)k 8/swg

  If the position versus time graph of an object is a vertical -6vt rmjj2 c5eline, the object is2 m6 -v5cterjj

  If the velocity versus time graph of an object is a horizoi q fxopg7 j(*iu+(b04 9hnl/f p6aolmq2rw b:ntal line, the object gfpf+w 0qiqb jrm:iu* 79 l(bpxl2/ 6(4naohois

  If the velocity versus(wnvhorxz;f4.a f/ -v7cd vz) time graph of an object is a straight line making an angle of 30 degrees with the tif . zcv 4w)7vh;vxdzrn (-afo/me axis, the object is

  An object moves 15.0 m north and then 11.0 m sokxy (sa897i/oepm2h9 m 1qpfwd iqw87 uth. Find both the distance travey2dpo8 71qiw 78kmx 9hm/fqsp(e a9w iled and the magnitude of the displacement vector.

  A boat can move at 30 km/h in still water. How long will it take to movek2+xwyl.j6(fz7y r r h 12 km upstream in hryw6+jlk7ryf.( x z2a river flowing 6.0 km/h?

  55 mi/h is how many m/s? (1 mi = 1609 m)4ls u-zl5 i)v hyoq,c+

  What must be your average speed snmsxr)wuj5g di0kvl.; ;7rpv63wz3in order to travel 350 km in 5.15 h?

  A runner ran the marathon (approximately 42.0 km) in 2 hours and 57 min. What :rh-0b7x lspg u.+p hzis the average speed of the runner 7lx- +hpg0prh.uzbs :in m/s?

  A car travels 90 km/h. How lok 9 kl x/.g ysyin)-2xeh,kxp*ng does it take for it to travel 400 km?

  A ly (light year) is the distance that light travels in one ye dm6t. 3sk -i3hp5ylktar. The speed of light 3k p.5lmdi6k ht- st3yis $3.00 \times 10^8 \; m/s$. 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 to the w .mrs hb++6kzside for 4.0 s, how far do you travel during bs+h.6z m+rkw this inattentive period?

  If you run a complete lozb/vl8+uxyd ynj.n tf-2g.d0op around an outdoor track (400 m), in 100 s, your averagexfzdb./yg802 tvdunjl.y-n + velocity is

  A polar bear starts at thel(oa afr-6g-0 w3y ns os/,/hn 9lwezk North Pole. It travels 1.0 km south, then 1.0 km east, then 1.0 km north, then 1.0 km west to return to i,( lon/ns 60fhgzal-kws 3ow-a9e/ yrts starting point. This trip takes 45 min. What was the bear's average speed?

  A polar bear starts at the North Pole. It trave7yyzztwnc f + x+08*guls 1.0 km south, then 1.0 km east, then 1.0 km north, then 1.0 km west to return to its starting point. This trip takes 45 min. What was the bewuz *n0 gcz+y 7+8fxytar's average velocity?

  You are driving home on a weekend from school h;g m3wc7bwq 6at 55 mi/h for 110 miles. It then starts to snow and you slow to 35 mi/h. You arrive home after driving 4 hours an63gqm;w7w hbcd 15 minutes. How far is your hometown from school?

  A motorist travels 160 kxxbk(j6h4mi :t7 vn2v m at 80 km/h and 160 km at 100 km/h. What is the average speed of the motorist fo4tbnkx 7vv(x6hm:2 ijr this trip?

  A motorist travels for 3.0 1j*ka6vczy,s1 ,1 fnz w keuq(h at 80 km/h and 2.0 h at 100 km/h. What is her average speed for the tripnkcy,,1kv ezz6 1fs*w(qjau1?

  An airplane travels at 300 mi/h south for 2.00 h and then at 250 mi/h+ j1kktbp dzt:,+t h,n2tzo :v north for 750 miles. What is the average speed for the tr+nz:kzt,vt+ khjt2 p ,o1td:b ip?

  In a 400-m relay race the aohp/. )g jt2ilnchorman (the person who runs the last 100 m) for team A can run 100 m in 9.8 s. His rival, the anchorman for team B, can cover 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 .gjto h li)p/2order that the team A runner not lose the race?

  A car decelerates uniformly and comes to a sto0i*u(fu*. w.hnbolm l)zl5qtd6f tj .p after 10 s. The car's average velocity during deceleration was 60 km/h. What was the car's deceleration while slowing df *l5bni u( fduqt*jo ml6.)h.l 0ztw.own?

  An airplane increases it7lxbwo p)p(,6ug gvw) s speed from 100 m/s to 160 m/s, at the average rate of x7) blw6pg vp), wgo(u$15 \; m/s^2$. How much time does it take for the complete increase in speed?

  A car traveling 60 km/h accelerates at the rate o;8ph-hqa(2i qvnqh7 sf $2.0 \; m/s^2$. How much time is required for the car to reach a speed of 90 km/h?

  A cart starts from rest and accelerates nu,ffw;.n;1f)nnv vn ;i del)at $4.0 \; m/s^2$ 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 pbzjhc,sn4/ cud-2)u 10 s. It then speeds up with a constant acceleration-2)un p,bshu c zcd4j/ of $2.0 \; m/s^2$ for 15 s. At the end of this time, what is its velocity?

  A cart with an initial velocity of 5.9 m/s experiences a constant accel0codrb6 rg( b4eration o64co(0 gdb brrf $2.1 \; m/s^2$. What is the cart's displacement during the first 6.8 s of its motion?

  A bullet moving horizontally to the right (+x direction) with a speed o8-80y q q(9rx1avtl9v/ eo hb ltla1jjf 463 m/s strikes a sandbag and penetrates a distance et18jab oq1 -99 xj0(lyhqr8lvtalv/ of 59.52 cm. What is the average acceleration, in $m/s^2$, of the bullet?

  A jet fighter plane is launched from a catapult on an aircraft carrier. h5d3uy/a:g gb:a dgj u5u+wo-It reaches a speed of 42 m/s at the end of the catapult, and th/-ajgg 5a3 bhu:wudu:g+5oy dis requires 2.0 s. Assuming the acceleration is constant, what is the length of the catapult?

  A car starting from rest moves with consta hrmw,h.w8,m/c xrz )int 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 20a neu89 wdj0w y16qii,0 m. What is its average acceleration98iw6iwj daq,1u 0ne y?

  An object starts from rest and undergoes uniform acceleratp1xhuzqj uaub*u4 qy:-day,,*vl/l5ion. During the first second it travels 8.6 m. How far will it travel during the u*p/,y ,u-* lyhjq4 db1xu al5vaz:uq third second?

  An object is moving in a ) .;ug 6qrwthxuu+ gsrgb4)*ostraight line with constant acceleration. Initially it is traveling at 16 m/s. Three seconds later it is traveling at 10 m/s. How far do6so+; *r utxr ggw).hu4qg)bues it move during this time?

  A car starts from rest and accelerates unif7sz;m28 xnols8 h f b84qwvxn-ormly 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 roas + kawj/ihc-0d can decelerate at about $5.0 \; m/s^2$ 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 has been waiting r0n em1szy+.eat the intersection starts ahead with a constant acceleratios.1z+n m ree0yn 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 uw 8sdb -8ij*zqpward with a speed of 12 m/s on the surface of planet X where the accelerj s*wbiq zd8-8ation due to gravity is $1.5 \; m/s^2$. What is the maximum height reached by the object?

  An object is thrown upward8.n lpu:x xm0 zk7 pex/nixnqu9a4(6w with a speed of 12 m/s on the surface of planet X where m4ulk7/(izp wn 9 x q60ue:xxa8 p.nnxthe acceleration due 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 unxzrglyr 7c1n1j akgf6j: (2 5a;e2l ipward with a speed of 15 m/s on the surface of planet X where the acceleration due to gravit a7i12er 16zagxflg2lc;n 5njyjr :(ky 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/sg+)oqgn l(w3, vyfeh2 on the surface of planet X where the acceleration due to gravity is hgy,w )ol2+vneq(3 f g$3.5 \; m/s^2$. What is the speed of the object after 8.0 s?

  Human reaction time is usually greater than 0.10 s. Ixyf*qr:)fioue m6ca4 u3 d+i2 jv(4br f your friend holds a ruler bet3xdq (f)+e24r4 m:r*fuu6o yvcbiia jween your 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 h qb07y sbp:n*6 bpa0dvelocity after 3.00 sp60s a 7bqh dbnyp0*:b?

  A bullet shot straight up returns to its starting point in 13 s. What is fl/io dv6 r4eo(,b)ij1 dxh2j the initial speed of the (r2h xdb oij dej)v f6,1/l4iobullet?

  A ball is thrown straight up with a speed a(f/+lsdf9ul-, a)z wg)vb pnof 36.0 m/s. How long does it take to return told9an s+w -u(bf,)za f /lv)pg its starting point?

  A ball is thrown downward from the topxa4r*k(qz e uj d32yn9 of a building with an initial speed of 25 m/s. It strikes thenr3*4u q j2kxed( zay9 ground after 4.9 s. How high is the building?

  A ball is thrown straight up with a speed of 30 m/s. (only fkt/9c* nj;;rx ihh i6kill in numerical value in the blanksi ;ik9c6r*hjk nh/;tx)
(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 straiqt s mf.au++7-1iogm f8ocqa+ght up into the air with a speed of 28.7 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 14 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 14.0 m above the point of contact a second time.  (数值)  $s$

  In Fig. below, what is the velocity at t = b qpr gdrudnfv 9zt5q,( ua5;zg.*,,a1.0 s?

  In Fig. below, what is the velocity /m0 wlndb /fo,at t = 2.5 s?

  In Fig. below, what is fp(4kq74o- rw/zm gzuthe velocity at t = 4.0 s?

  In Fig. below, what is the velocity at t = 5.5 s?lf nvc yn0*t46ox4k3d

  In Fig. below, what is the average velocity from 0 to 4.0v,vcixx)i8.*2*4/z 8:eo ch vd -aknm q pbhga s?

  In Fig. below, what is the average velocity from 0 to 6.0 s?w ) fushg rp:,p,qag6 8dzt+-s

  In Fig. below, what is the aczzza4 p( mvpwc:7/84jpe2bgf;3-t hp v(p eieceleration at 1.0 s?

  In Fig. below, what ipq). nth) z,.cnh8j* vltjxtgo w,w( 7s the acceleration at 3.0 s?

  In Fig. below, what is the ( a** 5i1at zost)ziiuaverage acceleration from 0 to 5.0 s?

  In Fig. below, what is the average acceleration from 0 ty0qh z g -rtvx/)hq 4:jec*c:wo 8.0 s?

  In Fig. below, what is the displacement f-4sm11dak1.y mcc 6u(c igibtrom 0 to 8.0 s?

Does a car speedometer measure speed, velocity? {speeb1anmve uhixhfwan,v y (w + 7//if:04d|velocity}

  An object can have a varying speed if its velocity is cons.ce)jooaf1c c qkj8, yza:03gtant.

  The velocity of an object can5h ;pyg+zf0)y,cucqa *.vrfj be negative when its acceleration is positive.

  If one object has a greater speed than a second obj 9m4jw y+;+0ggvaqmyhejj i 54ect, the first must have a greater acce+ayj v;5i4 h 4jye mqm+w0gj9gleration.

  Two cars emerge side by side from a tunnel. Car A is traveling with a speed o71*-2d 0pneu4halpjk ak(xxxf $60 \; km/h$ 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 itsr( y g4zesczulv 757z 2xd*q0w acceleration decreases.

  A baseball player hit (x7xtwwb/ ;yks a foul ball straight up into the air. It leaves the bat with a speex;/xby7 t(kwwd 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 its acceleration, acm;r o (tu1-thow does it change if air friction is ignored?ra o m-tt(1u;c

  As a freely falling object speeds up, lkny( 0u xg 8r,d,x10 9)nbcogmmdx f9what is happening to its acceleration, how does it change if air friction CAN NOT be ignocd0nd0rx )m1fbl9(y xum8,ngo ,xgk 9red?

  An object that is thrown vertically upward w :q: b sko mjngep/3v-0mydezb:l9id75 h:7ny ill return to its original position with the same speed as it had initially if air resistance is negligible. If air resistance is appres :d7:dbkn0ei9hy 75lbvpe :qn y zmg/oj3: -mciable, how will this result be altered?

  An object can have zerk9c*jrlgx s 26u-+t mfk :5a zpn+4yhuo velocity and nonzero acceleration at the same time.

  An object can have nonzero velocity and zero accerd6-:emrc6t 9k*l qqc leration at the same time.

  An elevator moving from the second flo:adk:8ea :vsx or to the fifth floor making no stops along 8:ask xdv:a e:the way has zero acceleration all the time.

  A rolling ball moves lqp6tyutuagliusj :11, 286a from $x_1=2.2 \mathrm{~cm}$ to $x_2=-5.6 \mathrm{~cm}$ during the time from $t_1=1.5 \mathrm{~s}$ to $t_2=5.6 \mathrm{~s}$. What is its average velocity?  (数值)  $cm/s$ (only fill in numerical value please)

  A particle at $t_1=-3.8 \mathrm{~s}$ is at $x_1=2.1 \mathrm{~cm}$ and at $t_2=4.4 \mathrm{~s}$ is at $x_2=7.9 \mathrm{~cm}$. What is its average velocity?  (数值)  $cm/s$

  A person jogs eight complete laps an ak3(n)8 gg/y8 xicwxround a quarter-mile ($1 \; mile = 1609 \; m$) track in a total time of 8.5 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 90 m away c z)xnrqc l9 uk.j89jr*8pc;iin 12.6 s. It then turns abruptly and gallops halfway back in 4.7 s. Calculat9c.p)ru k 9z lq jcnrci*8xj;8e (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 frzn.li0tf 685pft2l(g9 gafesnd04db om $12 \; m/s$ to $23 \; m/s$ in 5.7 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 / q+ i-btnm*bv$21 \; m/s$ to rest in a distance of 73 m. What was its acceleration, assumed constant?  (数值)  $m/s^2$

  A light plane must reach a speed r5 ih*rf ;0fbar ri,6 7k0auazof $32 \; m/s$ for takeoff. How long a runway is needed if the (constant) acceleration is $2.2 \; m/s^2$ ?  (数值)  $m$

  A world-class sprinter can b9i p++3 /feae 2nj vrcb+zmgs1urst out of the blocks to essentially top speed about9b 3ms p/cnfrzga++1je +2 iev $11.1 \; m/s$ in the first 14.3 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 uniformly from a sp saofkg1;* kh0eed of $20 \; m/s$ to rest in 4.77 s. How far did it travel in that time?  (数值)  $m$

  In coming to a stop, a car leaves skid marks 92 m lozru6,q4j, r2p3 zip el91ni ipng on the highway. Assuming a decelerati,lpzp4uz26niij e1 3 rrqi,9pon of $7.00 \; m/s^2$, estimate the speed of the car just before braking.    $m/s$

  A car is behind a truck going gwdwce,9( f k4e 3x7gy$25 \; m/s$ 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).    $m$