Suppose that an object travels from one poi dr8as28 s k;zliqix4 )7soco4:z, gzdnt in space to another. Make a comparison between the displacement and the distance trs;:ri2qd88 zoscagks z 74d, 4xzl)ioaveled.

  When is the average velocity of an objecokq5*5blb, ift equal to the instantaneous velocity?

  A new car manufacturer advertises that their car can go "from zero to sixvl9b ktz:og0 .ty in 8 s". This is a descriv z bk0lg9:.toption of

  An object moving in the +x axis experiences o6vppma)nx d 68ek4a keeyvps89/ y)9an acceleration of $2.0 \; m/s^2$. This means the object is

  Suppose that a car traveling to the East (+x directi5frd4 cu0q)/bqzk 5 nqon) begins to slow down as it approaches a traffic light. Make a statement concerningd 50qnbcqz5ufq k4) r/ its acceleration.

  Suppose that a car traowp3irt4 orn(i/o 4wle+3u*r veling to the West (-x direction) begins to slow down as it approaches a traffic light. Make a stateme*o4u lrwe /t i(rrin+ owpo334nt concerning its acceleration.

  Suppose that an object is moving with a constanp 0(.md+j8emrw vp4r pt velocity. Make a statement concerning its arv e.4(wp+jmr 0 pdp8mcceleration.

  If the velocity of an object is zero, doeob5 2 xn.hqh0vs it mean that the acceleration is zero? Support your anhxqo50v . 2bnhswer with an example.

  Can an object's velocithwh)6m4dj8el2 gn )zjy change direction when its acceleration is constant? Support yourh 8 m6dl)gn2h)wzje j4 answer with an example.

  Suppose that an object is moving with constant acceleration. Make a stateps+jy h)iygn8;:( e qfment concerning its motion with res8):iyhse;pqg f+jny (pect to time.

  Can an object have increasing speed while its accelera em 6h8 tdk98mff z;n;ks:g7lxtion is decreasing? Support your answenfdxefhks zmkt68 8 7l; :mg9;r with an example.

  Suppose a can, after an initial k*rhyg;m99 dqqya)9 mfl4su p4ick, moves up along a smooth hill of ice. Make a statement concerning its fr94*4d ;uaymp ) 9ymghqlq9sacceleration.

  Under what condition is average velocity equal to the average of the object's em :gjt +cs,o.initial an+mso:e, .ctgjd final velocity?

  Objects A and B both start at rest. They (9evi 79bdk sqsphn n02m u4a1both accelerate at the same rate. However, object A accelerates for twichn9isa 7(1sep 2b09 uknvd 4mqe 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 from rest. They both accelerate at the same rate. Hcra)tnr1,d u+1y ix9 vs*,hraowever, object A accelerates for twice the time as object B. What is the distancda1 ay9vcrh sixur1rt,) *+,n e traveled by object A compared to that of object B?

  When an object is released from rest and falls in the abs)nj26badm3qa c c wq5+ence of friction, which of the following is true concern6b q2nwa3 5)cm+dqac jing its motion?

  When an object is released fr cm36oe97d ct7rvrb2hom rest and falls in the absence of friction, which ofc oed7 7rrt 9vb3chm62 the following is true concerning its motion?

  Suppose a ball is thrown straight up. Make ac 4u; +lvs.rgr3z 2(-usrs7brz(mjy 0n.mj ft statement about the velocity and thr ts+.- mjnvj .rs7zu42rbzl0cr( fy( gums;3 e acceleration when the ball reaches the highest point.

  Suppose a ball is thrown . .kry;i1/a yyv 7ptktstraight up. What is its acceleration just before it reaches its highest poiykkip 7a.t/yt vy1. r;nt?

  Suppose a ball is thrown straight up, reaches a mkty h 1k v afi7v7*fdkka;2:k-aximum height, then falls to its initial height. Make a statement abod* 71v-2 7k;fk iytaak:fkhvkut the direction of the velocity and acceleration as the ball is going up.

  A ball is thrown straight t zn5mo+(kenl85ug p ;bnpx7/up, reaches a maximum height, then falls to its initial height. Make a statement about the direction of the velocity and acceleration as the ball tm8zn nop7+ 5e;/knl gx pbu5(is coming down.

  Suppose a ball is thrown downward in the absen+ ww5n c3:6w 4adcsizgce of air resistance. Make a statement concerning its acceleratin4 aw3zc65c:g dw+si won.

  Suppose a skydiver jumps lmkqvl; x)q.9morf*, from a high-flying plane. What is her acceleration when she she reacq 9.ll )*fxmv rok,m;qhes terminal velocity?

  A ball is thrown vertically upward with a speed v. An identical second ball ifv ycg0qn759 :yez rxd ix :j.j7p+0eyku4gv 3s thrown upward with a speed 2v (twice as fast). What is the ratio o3ncgr54kv0f y: 0v9yzudx7ji+. jx e yqe:g7pf 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 th//1h8v7ai far rm0q rgwn3 1t(x 8 kce*jb0kzqe top of a building. One second later, ball B is dropped from the same buiej0hz r1k/ 1mgqrf 8w*0 k/3b8x7ac(trnaqi vlding. As time progresses, the distance between them

  Ball A is dropped from the top of a building. Onet *yx2z.8p k-ht7lvws second later, ball B is dropped from the sametvs-z7 2ht.k *y lxw8p building. As time progresses, the difference in their speeds

  Two objects are thrown from the top of a tall build-kreb-j4lt6k2 e9gm;u0 mf.p,v ln nuing. One is thrown up, and the other is thrown down, both with the same initial speed. What ktvgmu nj ,u ke6 bmp4;r2el9n-0.-fl are their speeds when they hit the street?

  A brick is dropped from thep8ycvn s4vx3 o /;scc6 top of a building. A second brick is thrown straight down from the same building. They are released at the same time. Neglect air resistance. Compare the accelerations of the two br cv4 n6/;v8py sc3xscoicks.

  An object is moving with constant non-zero velocity in the +x axibs/4uek7 x7acs. The position versus time graph of t be7xak /cs74uhis object is

  An object is moving with constant non-zero a ouhy5o7,5qka cceleration in the +x axis. The positio7y ho5,kouq5a n versus time graph of this object is

  An object is moving with constant non-zero velocity in the +x axis. The veloci j gyj7yze m/w4.h k7oiz2;mm5ty versus time graph of this object iyj.7khz; i yw7o2jm/ ze5 4mmgs

  An object is moving with constant non-zero acceleratbm.xzz:3 4ffhion in the +x axis. The velocitfhx .:zmz 4bf3y versus time graph of this object is

  The slope of a position versus tigl5q0lel 3t)gb ipgr0.c cy6 -me graph gives

  The slope of a velocity veri+q *8fycy7q55t8 xh ka wnhoq()2cvesus time graph gives

  The area under a curve in an acceleration versus time graph x.he m-z1.d3ml 0gz0v * 0 rq*ocjguhygives

  The area under a curve in a velocity versus time graph give6um zc j,3xsitj p))3xs

  If the position versus time graph of an onoo x83;mxa.dbject is a horizontal line, the object ix3x8 mo.; odans

  If the position versus time graph of an object is a vertical line, the objl,wi:,-ggn 6m/j dteqect is,wntej:i/gq,6 - dlgm

  If the velocity versvpdcy9rrzfwk22h en; 0 l9mr+m9 3u9b us time graph of an object is a horizontal line, the object is2w3;2ky+r0rml99 fmcr9 zen9vhbdu p

  If the velocity versus time graph of an object is a straight line making and,s4+v bta.jx dw-a( w angle of 30 degrees with the -bddstw(4w+, xaa .j vtime axis, the object is

  An object moves 15.0 m north and then 11.0 m sout d, xwgcwxnh2woo)zvvh 2,;/ 9h. Find both the distance traveled and the magnitude of the displacement vectorhh9xwvc2x,d2 g oozwn/ ; ),wv.

  A boat can move at 347:pqg wpc.;*yvp *m 0jydq gm0 km/h in still water. How long will it take to move 12 km upstream in a riverqc ygmy4p0:j g* dm*7.;vwpqp flowing 6.0 km/h?

  55 mi/h is how many mzupx;xr h g8 d65zb.m,/s? (1 mi = 1609 m)

  What must be your average speed in ordersh0gh7j 3;qtfs0 u y0te-e i1h to travel 350 km in 5.15 h?

  A runner ran the marathon (approxima7 .nkoj iqhc- x/n/ub4e /:vvmtely 42.0 km) in 2 hours and 57 min. What is the average speedq k x -b/cnon4./viujh/vm:e7 of the runner in m/s?

  A car travels 90 km/hv 4 tf2w8;:qmqgx7hl vp9t bp5. How long does it take for it to travel 400 km?

  A ly (light year) is the distance that light trave t qmn67 ekxmc33y5 sj9k2r-tqc,px5 mls in one year. The speed of light ir6m,tc 5 7qnm ext2sckqpj5 x3k9y-m3s $3.00 \times 10^8 \; m/s$. 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 rzhcmk2k.c7tiuc0 qr s (6 ,d.ioad and you look to the side for 4.0 s, how far do you travel during tz7k(06r mc .tsihq uc2c,.kdihis inattentive period?

  If you run a complete ldk9*zs 3no8s ioop around an outdoor track (400 m), in 100 s, your average velociis *9skz3 8ondty is

  A polar bear starts at the North e3q4b n7xk* mdPole. 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. This trip takes 45 xd4b*3 m qken7min. What was the bear's average speed?

  A polar bear starts at the North Pole. It trqai aqvi*:f.d7n5wo u-4 urdx-v g00vavels 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 take 7-0avqfdr-u xvn0i v45qw g* aid.ou:s 45 min. What was the bear's average velocity?

  You are driving home on a *8hhkk j. zl,nweekend from 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 hours and 15 minutes. How far is yourn, 8 zk*hlhjk. hometown from school?

  A motorist travels 160 km at 80 km/h and 160 km at 100 km/h. What is ofhsgcv jb54a5t k4;.rnq+q /the average speed of the motorist for+/onk ar 4fjg;sb5t45q. q cvh this trip?

  A motorist travels fo cti tbfc-9t)r;tai:/r 3.0 h at 80 km/h and 2.0 h at 100 km/h. What is her averagetrc;i9-t/)ftab :c it speed for the trip?

  An airplane travels at 300 7/h ydu-w9 rqe.ek/j bmi/h south for 2.00 h and then at 250 mi/h north for 750 miles. What is the averee/yr-jk w9q.bh7/ ud age speed for the trip?

  In a 400-m relay race the anchorm,5,ga1.k gr ;va 5zcf xlj5xwpan (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 staw5pg.,f1j r;k5vacx xz a g,5lrts the final leg of the race, in order that the team A runner not lose the race?

  A car decelerates unifo6hxrcx;ph2cb9;/ q ufc( dv 3prmly and comes to a stop after 11 s. The car's average velocity during deceleration was 56 km/h. What was the car's deceleration while slowin;x 3frp xbc;/9c qu6vc hp(hd2g down?

  An airplane increases its speed from 100 m/s to 160 m/s, at the averav9 53gp7dspn/vv(* ( tql wwojge rate of g(9 5ndp ovq*/7 w3ptv(lj svw$15 \; m/s^2$. How much time does it take for the complete increase in speed?

  A car traveling 60 km/h accelerates atfl-c8y x:8 fnoqa3,9h3 o9s f1invazz 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 accelerav p79h-yk1qud tes 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 s; 5ngpg4 :7 lcbb4dwkh v9jpbq0 cmm*6peeds up with a constant acceleration of ldb g4j*mg9cvpw7b0 4nc:pbm6 q; k5h$2.0 \; m/s^2$ for 15 s. At the end of this time, what is its velocity?

  A cart with an initial velocity of k 3 jfil8x5m685lk9t k bp73tg iheud07.0 m/s experiences a constant acceleration of p8fh0 mulkk97i t5xb68d3lg3ke 5ji t$1.5 \; m/s^2$. What is the cart's displacement during the first 6.5 s of its motion?

  A bullet moving horizontally to the right (+x direction) with a speed o1mp9 (xxq1b jhf 288 m/s str1xq p(9hx mjb1ikes a sandbag and penetrates a distance of 12.44 cm. What is the average acceleration, in $m/s^2$, of the bullet?

  A jet fighter plane is launched from a catapult on an aircrafteay/yuk ws6p 7p/;mtzu4 8 v80epl c8v carrier. It reaches a speed of 42 m/s at the end of the catapu v8sy/4 6zp0pyt8c;a/mlp vuu8 ek7welt, 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 constant acceleratid*vmo ch fq(/yhs p-yu)-o+ r-on 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 dista z zjh+(/rl6b5c:ooponce of 200 m. What is its average acceleration/l5hjc+b oopo6 z:(zr?

  An object starts from rest and undergoes uniform acceleration. During the fi;hk) wtq1hy8wxt5( kdrst second it travels 5.2 m. How far will it travel during 8;wkd )ktqtw(y5hh1 xthe third second?

  An object is moving in a straight line with constant accelerationrr usy3u0 -5(5jx a3 l+jsdfiy. Initially it is traveling at 16 m/s. Three seconds later it is traveling at 10 m/s. How fardys3ar( uj-0ul s 5+y3fx5jir does it move during this time?

  A car starts from rest and acce5njx( duhkp0) lerates 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 dm9stny ls8ddwt .hz(d v:6q-9ue(j*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 caq4x hdeweimp w 6,gi(c ;c4(9br that has been waiting at the intersection stw ;4emxi(eb96,chi qpg dw c(4arts ahead with a constant 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 )5 2k*qr9vj p odw8ommspeed of 12 m/s on the surface of planet X where the acceleration due to gravity vdm8o9)5* q w jp2omkris $1.5 \; m/s^2$. What is the maximum height reached by the object?

  An object is thrown upward with a speed of 12 m/s on okc o-b s*pw4ccr k;5-the surface of planet X where the acceleration due to grbwks;o- 4ckp-oc5 *r cavity 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 of 15 m/s on the surfaiixa3ztmp 0(m icg69mf55h51i hm6d zce of planet X where the acceleration due to gra(3z mpi0hmg 5c5i6z h6 95maxdf mtii1vity 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 smrfh- -lqq(+6: agdli9gmfiubk,6t1 urface of planet X where the acceleration due q+6grq,g:-f hfm l ikld(aum-b6i1t9to gravity is $3.5 \; m/s^2$. What is the speed of the object after 8.0 s?

  Human reaction time is usually greater than 0.10 s. If your fridgcx4fq s k6/2end holds a ruler between your fingers and releases it withd/kgf s42cx6q out warning, how far can you expect the ruler to fall before you catch it?

  A ball is thrown upward 3yo/u2-iwo( wjdyhw3 -zb)fvat a velocity of 19.6 m/s. What is its velocity after 3.00 dozywiu-y2wj33(w ob- hvf ) /s?

  A bullet shot straight up returns to its starting point in 15 s. Wh q tv5-a;vnrwb(*oq+d5 q7ntx at is the initial speed of theq+r*q5;75bdv(na wxvtot-nq bullet?

  A ball is thrown straight up with a speed of 36.0 m/s. How long does it tg5a0t a m;u*edake to regaemdu t0*5 ;aturn to its starting point?

  A ball is thrown downward from the top of a buildi ida()8xw ra8mng with an initial speed of 21 m/s. It strikes the ground after 7.7 s. How hi ix8 8ra)(wdamgh is the building?

  A ball is thrown straight up with a speed of 30 m/s. (only fily (e:e. d,gq*pwh d5lel in numerical valu ly*p5g,q.:e (he wdede 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 t-. j8fr pxlr2air with a speed of 48.9 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 9 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 9.0 m above the point of contact a second time.  (数值)  $s$

  In Fig. below, what is the vedtcjrn(d ur i)5i8x 4:y)q)t6thq li9locity at t = 1.0 s?

  In Fig. below, what is the veloci 6 3hm0n0tnyhhty at t = 2.5 s?

  In Fig. below, what is the velocity aj y;vwt cp30u+t t = 4.0 s?

  In Fig. below, what is the vqln g /g6+ w58li lijy+-ir6hvelocity at t = 5.5 s?

  In Fig. below, what is the average veloc q.p/ushf5h/:qx5d xrity from 0 to 4.0 s?

  In Fig. below, what is the average ve*tge40ogs,r e locity from 0 to 6.0 s?

  In Fig. below, what is the acceleratl 15 m4mvyc*dj (ue7n uczll(+ion at 1.0 s?

  In Fig. below, what is the acceleration f0.i1t1hdwv0f )y 7yit lg2khg)v6q p at 3.0 s?

  In Fig. below, what is the average acceleration frc9j1 x2f5zkjou5,*wn4d l lhxom 0 to 5.0 s?

  In Fig. below, what is the average acceleratiot:mry9or vnb f( 2/xh4/iu c:rn from 0 to 8.0 s?

  In Fig. below, what is the disdif210 bi,iba 9nhs.vplacement from 0 to 8.0 s?

Does a car speedometer measure sperx2 g9ga ;(yq stl)lf.ed, velocity? {speed|velocity}

  An object can have a varying speed if its velocity 5ans+sfg g 3e5g41jmp (2gt gris constant.

  The velocity of an object can be nea6dj- 0v tjf6ogative when its acceleration is positive.

  If one object has a greater speed tha1tk(p 9( h c-sp 6cju2udoivp5n a second object, the first must have a greater accelerati(kcu5(p2upp9 i cj1 -svot hd6on.

  Two cars emerge side by side from a j57vx g;k+h irtunnel. Car A is traveling with 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 decreases. .wxf:5t) puu5 udbhp4

  A baseball player hits a foul ball jg4tmpc 50ap6 o xlx,2straight up into the air. It leaves the bat with a speedap 06xo, x p2mjg45lct 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 objebf8 abu:qz6s56jnl 8hct speeds up, what is happening to its acceleration, how does it change if fqnb: us685a8 j bl6hzair friction is ignored?

  As a freely falling object speeds up, what is happening to iu i9bq7un*l;d73qbz)z223k mm 96z lgs ii tiots acceleration, how does it changed) 7u s9zq 3i zl6kb;2l*qmtb zoi7nm 2ui9ig3 if air friction CAN NOT be ignored?

  An object that is thrown - p23dli rs;tqi18gyijjck1 1 vertically upward will return to its original position wi 1di1 p-1ijc3jkr2q8lyg;s tith the same speed as it had initially if air resistance is negligible. If air resistance is appreciable, how will this result be altered?

  An object can have zero velocity and nonzero acceleratz a7nbbv*g,c -ion at the same time.

  An object can have nonzero velocity and zero acc46 0ijmuxc jwk x-(v;meleration at the same time.

  An elevator moving from the second floor to the fifth floor making a2 a 9hw 1ubdm84+0 mqqcv-n7 eydbv2mno stops along the way has zero acceldy + e8w0a c2n v-7m2ubambqd9q4mh1 veration all the time.

  A rolling ball moves fromte k(tb p,8y pr 4py(cfbva;-6 7atu,f $x_1=3.0 \mathrm{~cm}$ to $x_2=-6.7 \mathrm{~cm}$ during the time from $t_1=1.8 \mathrm{~s}$ to $t_2=5.4 \mathrm{~s}$. What is its average velocity?  (数值)  $cm/s$ (only fill in numerical value please)

  A particle at $t_1=-3.7 \mathrm{~s}$ is at $x_1=2.7 \mathrm{~cm}$ and at $t_2=3.6 \mathrm{~s}$ is at $x_2=8.3 \mathrm{~cm}$. What is its average velocity?  (数值)  $cm/s$

  A person jogs eight comp;fq 17rp7pdu dlete laps around a quarter-mile ($1 \; mile = 1609 \; m$) track in a total time of 8.3 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 106 m away ib) hng igbkpv28+.ym2 n 8.3 s. It then turns abruptly and gallops halfway backk p. bny82m2gv+)bh gi in 4.5 s. 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 from ;.e ;78eqy;mou 8hbdwjkq tb9r8tfv7$13 \; m/s$ to $24 \; m/s$ in 5.3 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 4nb f1cj-h k( 5ovl+jk$20 \; m/s$ to rest in a distance of 84 m. What was its acceleration, assumed constant?  (数值)  $m/s^2$

  A light plane must rty9j y9hfd.0o tpba54each a speed of $32 \; m/s$ for takeoff. How long a runway is needed if the (constant) acceleration is $2.7 \; m/s^2$ ?  (数值)  $m$

  A world-class sprinte0z;e us(wa6fpez;4 o br can burst out of the blocks to essentially top speed abouzeaf;6(;0pbsw 4euz o t $10.6 \; m/s$ in the first 12.0 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 uniformlytbylm5ln*-u :f s9xu, from a speed of $17 \; m/s$ to rest in 4.66 s. How far did it travel in that time?  (数值)  $m$

  In coming to a stop, a car leaves skid marks 92 m longbc :f1.j gie8yorn.a+ on the highway. Assuming a decelerat.:y e 8fr.1jb+ iagocnion of $7.00 \; m/s^2$, estimate the speed of the car just before braking.    $m/s$

  A car is behind a truck gmjwl tav6vu8p4g wl ) j4l89s3oing $25 \; m/s$ 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. Aftergdne;q4kek6 9 exactly 27.0 min, tkqkd;n 6e4g9 ehere 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?    $s$