Suppose that an object travels from one point in space to another. wtdp.r6 /fnks/1+ ur v Make a comparison between the displacement and wrvk/n p6/f1stur+d. the distance traveled.

  When is the average velocity of an object equal to the mprve leqnq5f.gzu7c m 1()kc-.vi //instantaneous velocity?

  A new car manufacturer advertises that their car can goa iz,;bw-0nb/p+t2 ojuc 2ulz7 ,biwr "from zero to sixty in 8 s". This is a description0, twipa2/2b; zo 7b+,j ulwib-cznu r of

  An object moving in the +x axiss :q dm)q.xmyved5teg *09yv 4 experiences an acceleration of $2.0 \; m/s^2$. This means the object is

  Suppose that a car traveling to the East4jq (xkeye+3i (+x direction) begins to slow down as it approaches a t(4exiek+ qyj 3raffic light. Make a statement concerning its acceleration.

  Suppose that a car traveling to the West (-x direction) .rflrc2b 04 gzbegins to slow down as it approaches a traffic light. Make gb.f c4zlr0r2a statement concerning its acceleration.

  Suppose that an object is moving with a constant velocitl: a xnc7;ssd8;o;naa tv.onkx;5: umy. Make a statement concerning its accelerata57oak;xsml.dtnunx cs;:ao 8;nv:;ion.

  If the velocity of an object rlc75e:,zg +bx/ sxwk0(jr qbis zero, does it mean that the acceleration is zero? Suppsxk7r5r0bl qb,+/e ( g cjw:xzort your answer with an example.

  Can an object's velocity ch+ v /pjo,kg:qmange direction when its acceleration is constant? Support + pq:v,m/kg ojyour answer with an example.

  Suppose that an object is moving with constant accelera *;zv+vxkggp h;u- :yotion. Make a statement concerning zgo+gvxp:uvk y-; ;h*its motion with respect to time.

  Can an object have increa6z7 lfxzaz;79+fyjnu sing speed while its acceleration is decreasing? Support your z7n zfl z97jux6 yfa+;answer with an example.

  Suppose a can, after an initial kick, m h +;+qsr6*tquqi k,uvoves up along a smooth hill of ice. Make a sta + u+uikv*6,qsr; hqtqtement concerning its acceleration.

  Under what condition is average a, qx (fs as9vsxd.6n0n7p+vu3 pb+m dvelocity equal to the average of the object's initialmd9 dxs,+b p.7 avfaspu 6n+x(vq0ns3 and final velocity?

  Objects A and B both start at rest. They both accelerate at thefezi+ pe4ofg .ahip 6g/rz3 8f4 96rlo same rate. However, obgple zizrafr64e /34g8 9 i+oh.po6ffject A accelerates for twice the time as object B. What is the final speed of object A compared to that of object B?

  Objects A and B both start fro xng*f8d7xevv+ zq3 1lm rest. They both accelerate at the same rate. However, object 3lvgfq edx7+ 1x zv*n8A accelerates for twice 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 of o,3dt*ob0hdj e usjf-z z/k:2friction, which of the foll o bhzzduejd-f s to3*kj:0,2/owing is true concerning its motion?

  When an object is released from rest and falls in the absenowav w ae9 ea6ws;e47+ce of friction, which o+sae wova7 96e;ae 4wwf the following is true concerning its motion?

  Suppose a ball is thrown straighrr yldzp -e0*re0jo +5t up. Make a statement about the velocity and the acceleration when the ball -o*0zej err+5y r dp0lreaches the highest point.

  Suppose a ball is thrown straight up. What is its acceleration just befor;.x 04w/ro fiml)km soe it rea; 0/r .woil4 mo)msfxkches its highest point?

  Suppose a ball is thrown straight up gcb9z:lbvvl+: t99pjz 5eizy ,3ka4w, reaches a maximum height, then falls to its initial height. Make a statement about 9l4cl+t w 5vbje9 ayg3p,:9zzi : bkzvthe direction of the velocity and acceleration as the ball is going up.

  A ball is thrown straight up, reaches a maximum height, t*pu v)pr d/7owikp3(lhen falls to its initial height. Make a statement about the direction of the velocity and acceleration as the bappr ok(l)wp7/ vui d3*ll is coming down.

  Suppose a ball is thrown downward in the absence of air resistance. Make a stat74ic,ah4 v/we wqtn7g .al;njement concerning its acceleratiqvciahw4tn a/ n e 74,;.j7glwon.

  Suppose a skydiver jumps fro b7.wjyj5vv /xniu;e7m a high-flying plane. What is her acceleration when she she reaches terminbeynuj.j w5xv7;vi7 /al velocity?

  A ball is thrown vertically upward with a speed v. An identical second ball is 29ch vwffm/j:ikw6qd .uod ( (thrown upward with a speed 2v (twice as fast). What is the ratio of the maximum height of the second ballqu cjwdh (f/2m6 vkwf( .d9:io to that of the first ball? (How many times higher does the second ball go than the first ball?)

  Ball A is dropped from the top of a buitind zv1ar 5-ck8djbegjvkch/30, 2) lding. One second later, ball B is dropped from the same building. As time progresses, the distanj v2g i0 jtadkc3bedv1 k85hcrn/z- ),ce between them

  Ball A is dropped from the top of a building. One secov dc:icp8kdv,9 aqz61 hi/c*snd later, ball B is dropped from the 6 c v/c s8 pi:vdz9dhc*ik1qa,same building. As time progresses, the difference in their speeds

  Two objects are thrown from the top of a tqo+ o.2p9x jzoh0b.p tall building. One is thrown up, and the other is thrown down, both with the same initial speed. What are their speeds when they hit the sz0 jxoo.2. qtp o+p9bhtreet?

  A brick is dropped from the topxw28ndw wk 86cr+-m j; cp8mvq of a building. A second brick is thrown straight down from the same building. Theyvkw8 pn8;rj6 c wm8c+wqxm-d2 are released at the same time. Neglect air resistance. Compare the accelerations of the two bricks.

  An object is moving with constant non-zero velocity in the +x axis. Theh gg d6.*h+8:h;8g6jyzay qj*no mlcx position versus time graph8g j gqglc6zhjhmy6y*x8 d:+*.oan ;h of this object is

  An object is moving with constant non-zero acceleryy 92uj - wj9puu3qo:yation in the +x axis. The position versus time graph of this object i3o9yq9y2j:-u uu jpy ws

  An object is moving w) kmviy(xcp fy2 r+*3gith constant non-zero velocity in the +x axis. The velocity versus time graph of this og3 ) x2ypy( vkcmirf+*bject is

  An object is moving with constant non-zero 46 az;:g nodjlsg,n3vacceleration in the +x axis. The velocity versus time graph of this object igd ;v: 6o3nza ,lsng4js

  The slope of a position versuss6ucpqp(/ h4 7ht: rbs time graph gives

  The slope of a velocity versus tim rfhw4npi1-7 co/ ape9e graph gives

  The area under a curve in an accelerata e2aucst6*niqf1o - 5ion versus time graph gives

  The area under a curve in a veloc bsd8l6s+i,v v;,vwdaity versus time graph gives

  If the position versus time graph of an ob;ww5 1 uryfh jf.f9hj-5nab2zject is a horizontal line, the object iswrhfhu5y 5 fbz . 2j;jw-a9fn1

  If the position versus time graph of an object is a vertical line, thk,8jmq 4govr-p+jt 6fe object isjpgvkf q8 +mr-ot4j ,6

  If the velocity versus time graph of an object is a horizontal line, the objecr8u+vo8nl3 2ue h mq.wt w 8+mo.ev2uq8hnrl3uis

  If the velocity versus time graph of an object is a sryhr /kxb5qm+x:-,8u ) yxwx straight line making an angle of 30 degrees with the tim y:5q yw u-+b,m)sxhrxx/8k rxe axis, the object is

  An object moves 15.0 m north and then 11.0 nt6-6 lf6mw8h5xo ywtm south. Find both the distance traveled and the magnitude of the displacemw6fy8 lmt-w6to6 x5hn ent vector.

  A boat can move at 30 km/h in still water. How long will it take to movm thcs3mz s/mo mc-a(4hi)a: ;e 12 km upstream in a amsm a4h)tis o (c-z;:m3mh c/river flowing 6.0 km/h?

  55 mi/h is how many m/s? xzx 3otr-o4i, (1 mi = 1609 m)

  What must be your average speed in order to travel 350 km ibv:f6ow8i/*fqf *va on 5.15 h?

  A runner ran the marathon (approximatelyn 2 q+/of /rm6avsrw0s 42.0 km) in 2 hours and 57 min. What is the average speed of the runner i2f+0vom /naswr/rs q6n m/s?

  A car travels 90 km/h. How long does k)t/o5lamuk--8oim3z9yp ig7 zk) l j it take for it to travel 400 km?

  A ly (light year) ise1*1ba/ t+3h+ i id3 raebkleaqt 6*cu the distance that light travels in one year. The speed of light iek3+h iileq*cu6+* rd3t 1 abaea1/ bts $3.00 \times 10^8 \; m/s$. 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 straiahcpl+: q1 w(ff6n )u vunf1*ight road and you look to the side for 4.0 s, how f nnu 1(fvu 1wcphi*)ffq+a :l6ar do you travel during this inattentive period?

  If you run a complete loop around an outdoor track (400 m), in 100 l:s koam7c:j3im 3wjk6cn9 9b s, your average velocity 3k oc6k9na ij:37mwlmbsj9c : is

  A polar bear starts at thesq/c-un 2ev6wl+ k1bx 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 its starting point. e2nl vx6u qs/b-cwk1+This trip takes 45 min. What was the bear's average speed?

  A polar bear starts at the North Pole. It travels 1.0 km south, the e/4i;b p:avmen 1.0 km east, then 1.0 km north, then 1.0 km west to return to its starting point. This tripp4b;iev ame/ : takes 45 min. What was the bear's average velocity?

  You are driving home on a weekend from school -fbd+dij u /2tlur:p x -:s9ikat 55 mi/h for 110 miles. It then starts to snow and you slow tox2b9+djf-k :i -lrsdu/t:up i 35 mi/h. You arrive home after driving 4 hours and 15 minutes. How far is your hometown from school?

  A motorist travels 160 km at 80 km/h and 160 km at 107:ajnuh./ k (g+lprmzqm 8b7a 0 km/h. What is the average speglz(:h 7/ kq87jpn+ru m.aambed of the motorist for this trip?

  A motorist travels for 3 )m tbs(d18mh6ags+a(4yv n ne.0 h at 80 km/h and 2.0 h at 100 km/h. What is her average speed s+mga v db1anhye()(6s 84ntm for the trip?

  An airplane travels at 300 mi/h south for 2.00 h and then at 250 mi/h north for0*n0 hu hrq )./mhfio 24pkrrb 750 miles. What is the average speed for the tripb nh04o0uk*qmh/)r.hpi2r r f ?

  In a 400-m relay race the az raqte2ruz.9v. z/l/nchorman (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, ivt2./ urze9z zar.l q/n order that the team A runner not lose the race?

  A car decelerates uniformly and comes r16 amgy2 (n;+elp hsxto a stop after 12 s. The car's average velocity during deceleration was 46 km/h. What wn(+peh;1ms62g yalxras the car's deceleration while slowing down?

  An airplane increases its speed from 100 m/s to 160 m/s, at th- j+uy1e2i, p 4v3f5yguit knye average rate of eijy ug+v-k2n34pty,u1f5 iy $15 \; m/s^2$. How much time does it take for the complete increase in speed?

  A car traveling 60 km/h accelerates at the4b6h (p7j of/jq, dz uvyg(+iw 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 a,b3ytsealzh.2 ng9 6e4r*pwk/ew i g6ccelerates 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 10 s. It then speeds up with a cons*v 7 qtw,tzrcv8c*fh+tant accelerationrt7qc* zfcw+ v*,th8v 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 2.1 m/s experiences a constant acceleration o*cf( c2oius. r2s(c u.*o ricff $4.6 \; m/s^2$. What is the cart's displacement during the first 7.5 s of its motion?

  A bullet moving horizonxdi0p d80vat k x3qy2r3tztq3nn -9i76nk/p vtally to the right (+x direction) with a speed of 590 m/s strikes a sandbag and penetrates a distance of 18.07 cm. What is the axin0dkzdt90 2 px6qv/a qtn vy8knr-3p3t73 iverage acceleration, in $m/s^2$, of the bullet?

  A jet fighter plane is launv)n ms8quhtpwz5a (4b9r7id 5ched from a catapult on an aircraft carrier. It reaches a speed of 42 m/s at the end of 8 bu()5mtdvq749n pwiharsz5the catapult, and this requires 2.0 s. Assuming the acceleration is constant, what is the length of the catapult?

  A car starting from restfz6atb1h0dhd0 kr m;1 moves with constant 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 i(p) l:d fc)i fo0hpoo09p1 inhn a distance of 200 m. What is its average accelerifl1 0(p)hfpo h d on)io:0c9pation?

  An object starts from rest and undergoes uae hlxg:hb kl z2t;.b;2nl hd4f-4 o.p3vu,ae niform acceleration. During the first second it travels 2.9 m. Howug 4xhh bot;belle -fadnl.a3.v,2k; z2 :ph4 far will it travel during the third second?

  An object is moving in a straight td5ik 8/9so5)ziy5 -dqb/ ;hausg dwxline with constant acceleration. Initially it isd8qbkzh ) 5;sxa/5-g9i 5tody d/uw is traveling at 16 m/s. Three seconds later it is traveling at 10 m/s. How far does it move during this time?

  A car starts from rest and accelerates unit1hv7 v 2nfx9uformly 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 roa * -fekfze+4;bhr)anjd 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 hag:2c th)gvja ie 6s q*05b2tjbs been waiting at the intersection starts ahead with a constant accelerati 0ibe:qc j2jg g2sv)a56tbht*on 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 of 12 0 t n-z/oklqx5.4 fy)pjqtj,ym/s on the surface of planet X wherflnq4,j5t zopxk-/j t 0)yq.ye the acceleration due to gravity 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/ebpoauk3wg(;f )-p+ ys on the surface of planet X where the acceleration due to gravity 3ae-p bpfogu(+ kwy;) is $1.5 \; m/s^2$. How long does it take for the object to reach the maximum height?

  An object is thrown upward withs1o8sn6 zc-d h a speed of 15 m/s on the surface of planet X where the acceleration due to gravity is d o1-zncs8hs6 $2.5 \; m/s^2$. 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/15p vb5 aqxlkdwd16..oy xp +fs on the surface of planet X where the acceleratifob1px.xawq5 k65y .p l+d1 dvon due to gravity is $3.5 \; m/s^2$. What is the speed of the object after 8.0 s?

  Human reaction time is usually )s *ep 43qfaq5y :wyyjgreater than 0.10 s. If your friend holds a ruler between your fingers and rel a5e yf4jsyqwq3py):*eases 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 vpzct67 bg45x b6g*+jm mn0ity elocity after 3gp5zt0c4m byg7jb6 *n+mxt i6 .00 s?

  A bullet shot straight up returns to its. 40 sbu *gywa*32ndgs(bt hbo starting point in 17 s. What is the initial speed of the bu gbbghsad*s nw 3.*buo4( 2ty0llet?

  A ball is thrown straight up with a speed of 36.0 m/s. How long does it tn,y(nw4h.a:f* uvlek nlhq;6 ,c(chtake to return toe( ,4anwhn( uv6n lc *hy.fh,:kcq;tl its starting point?

  A ball is thrown downward fr 7en tljpik/ki )izm80/ao (8aom the top of a building with an initial speed of 25 m/s. It strikes the ground after 5.0 s. )tki87 0lz8ijik //apeon( ma How high is the building?

  A ball is thrown straighg*,44g(vpz sjk 2lbf kt up with a speed of 30 m/s. (only fill in numerical vall4fzkb4(g kg *pv2 ,sjue in the 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 3yt 3z*zjcnkja4 7 5svjdr0m-air with a speed of 33.8 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 10 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 10.0 m above the point of contact a second time.  (数值)  $s$

  In Fig. below, what is the veloqjyx-j +m,knt 8d84whcity at t = 1.0 s?

  In Fig. below, what is the velohw(x du3-3kh pcity at t = 2.5 s?

  In Fig. below, what is the velocia (tsnxk /q3pi+c58gnty at t = 4.0 s?

  In Fig. below, what is the velocity at t = 5.56kyzc/meh qz1 e2p-,d s?

  In Fig. below, what is the average veun*)6wk1py zksh.hv ) locity from 0 to 4.0 s?

  In Fig. below, what is the wxot1t 7.8rg xaverage velocity from 0 to 6.0 s?

  In Fig. below, what is the accelerat(:k2 0; n0bulx zsqw; .ohzr gw.uw1epion at 1.0 s?

  In Fig. below, what is the acceleration at 3.0 s/nrdo3b n1f* 5n ebx0e?

  In Fig. below, what is the averavfn -hrbsfo cf3py567/ ow5 / g;f;uwis,m+rcge acceleration from 0 to 5.0 s?

  In Fig. below, what is the average am l8 ga)-c5zucatv m:6cceleration from 0 to 8.0 s?

  In Fig. below, what is the displacement frdqsg6cq z y.2+elh-zejg) y2*.. ipiuom 0 to 8.0 s?

Does a car speedometer measure speed, velocity? {speed|velocityc(l jpeus p:n- 34ey)y}

  An object can have a varying speedc,opq 0ed9f4zki j aqkr-)munbf15( 5 if its velocity is constant.

  The velocity of an object cr jnxsu,h n9a9 x55c.sr(c s:oan be negative when its acceleration is positive.

  If one object has a greater speed than a k msv9px4 8-yaioiw 2-uvh2+ t 0pd3wqsecond object, the first must have a greater acceler2vompq 0ps3+wukya w4d 2i 9v8t-hi- xation.

  Two cars emerge side by side from a tunnel. Car A is traveling with a speed ohoad0 8bt/ymb r(;wlq bn :l84f $60 \; km/h$ 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 de)i0p bnsrk /*wcreases.

  A baseball player hits a foul b 7svw +krtlu*wdr s(5:all straight up into the air. It leaves the bat with a speedrut:*sw 7wv+r5 l (kds 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 objz it9phl/* kq z*p(u9)qab 0jzect speeds up, what is happening to its acceleration, how does itz* jap kuz*z0/9p i9b)hlqq (t change if air friction is ignored?

  As a freely falling object spy3mm:22 vi 7uep hs/-wh;ciig eeds up, what is happening to its acceleration, how does it change if air friction CAN NOT be73yh:/ hgmi;2iu- imp ecvs2w ignored?

  An object that is thrown vertically upw dlk;xs2kl;fi04cw f0ard will return to its original position with the same speed as it had initially if air rescwsl4 l0 kkxf0d;i 2;fistance is negligible. If air resistance is appreciable, how will this result be altered?

  An object can have zero velocity and nonzero ac 8c (.;s vidbqj,g b-6ifpeho6celeration at the same time.

  An object can have nonzero velocity a04b w),d wdhdah,mm; end zero acceleration at the same time.

  An elevator moving from the second floor to the fifth floor making no ln4jf.aamh4 g/ p7 ms2stops along the way has zero acceleration all th gmsnm. flj4a a2/7ph4e time.

  A rolling ball moves7vw zus83j2, lpsfk *x from $x_1=2.0 \mathrm{~cm}$ to $x_2=-5.2 \mathrm{~cm}$ during the time from $t_1=1.7 \mathrm{~s}$ to $t_2=6.0 \mathrm{~s}$. What is its average velocity?  (数值)  $cm/s$ (only fill in numerical value please)

  A particle at $t_1=-2.6 \mathrm{~s}$ is at $x_1=2.6 \mathrm{~cm}$ and at $t_2=4.0 \mathrm{~s}$ is at $x_2=8.1 \mathrm{~cm}$. What is its average velocity?  (数值)  $cm/s$

  A person jogs eight complete laps around a quarter-mile lv9ak z2gc 8rmjz90 k;($1 \; mile = 1609 \; m$) track in a total time of 10.2 min. Calculate (a) the average speed  (数值)  $m/s$ and (b) the average velocity    $m/s$

  A horse canters away from its trainer /k v;n/cvyp/cin a straight line, moving 112 m away in 13.9 s. It then turns abruptly and gallops halfway back in 4.7 s. Calculate pcnkvv;y// /c (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 fromh rgmtfs6tp:j)(.mf p8hr8s 8 $13 \; m/s$ to $24 \; m/s$ in 4.0 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 /k x dkwr1/a.u86rgzy$22 \; m/s$ to rest in a distance of 69 m. What was its acceleration, assumed constant?  (数值)  $m/s^2$

  A light plane must reach a sqif 57ya:iuo7bq7mk; peed of $28 \; m/s$ 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 burst out of the blocks to essentially top spee98 imk:-z+ycxas/okk d aboum8 oz:x/kscy k 9-+iakt $11.4 \; m/s$ 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 uniformly from a so6gp1v,*mtttrm5 hu)k0zts) c yaq8j yp7.f5 peed of $17 \; m/s$ to rest in 4.55 s. How far did it travel in that time?  (数值)  $m$

  In coming to a stop, a car leaves skid marks 92 m long on the highway. Assumi4+mii6 d kyo*a56 xu-pdut. sb7hk+fp ng a decepxdb6o6pu- idh* kk+tify. su 4m 7a+5leration of $7.00 \; m/s^2$, estimate the speed of the car just before braking.    $m/s$

  A car is behind a truck gxi ,dx+f-ni-poing $25 \; m/s$ 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 t*a o y( p,mwp1cw.5ijless than 30.0 min. After exactlyw1o*pamj(,5y t.wi cp 27.0 min, there are still 1100 m to go. The runner must then accelerate at $0.20 \; m/s^2$ for how many seconds in order to achieve the desired time?    $s$