Suppose that an object tzmra u u;7*-mlravels from one point in space to another. Make a comparison between the displacement and the distance tr ;a7luzr um*-maveled.

  When is the average velocity of an object equal to the instantaneous velocit pctdnsrhfd2.e-/2 4 ay?

  A new car manufacturer advertises that the8bqjzlnujk bt8 , ;a*ak.o:n4 ir car can go "from zero to sixty in 8 s". This is a description;az8l8jjbqkat 4 n.un,o b*:k of

  An object moving in the +x axis experiemrnx mz u7wj8z n.z. 1a2r9x(dnces an acceleration of $2.0 \; m/s^2$. This means the object is

  Suppose that a car traveling to the East (+x direction)rre4*vv ,r zw+4*ng)fg 2okl k begins to slow down as it approaches a traffic light. Make a statement concerning its acceleratio ,w n r4r4grv+vel)zfkk*g* 2on.

  Suppose that a car traveling to the West (-7qbhzkr*gmhe:x x)l oe0 hy rp66 ;;+hx direction) begins to slow down as it approaches a traffic light. Make a statement concerr khge0hqr h*+ypm)h6 lo x;x7e;:z 6bning its acceleration.

  Suppose that an object is moving with a constant velocity. Make a statement co- )vv)cna te40fpgci.nce)f4te0gccan i)p.v v -rning its acceleration.

  If the velocity of an object is zero, does it mean that the acceleration1e-qpcv.t8e sr q) luu4m6(cr is zero? Support your answer wm1u-ruecv6rq4.cs)plqe( 8 tith an example.

  Can an object's velocity change direction oa0fe5tr qun) cx8/) owhen its acceleration is constant? Support your answer with0 )no)aetocq/8 u5 rxf an example.

  Suppose that an object is moving with constant accele,tdi2nbc*w1jd k:x v6ration. Make a statement concerning its motion with respd i:nx tkdbw2*cv6,1ject to time.

  Can an object have increasiq qhfd334hgh4 ng speed while its acceleration is decreasing? Support your answer with an examplefq hg 3d34q4hh.

  Suppose a can, after an initial165b76kzsdquq9n+ktu c p5 i p kick, moves up along a smooth hill of ice. Make a statement concerning its accelerazk55bp+nk 971 ciquspd6utq6 tion.

  Under what condition is average velocity equal to the avj g bn qok8s kdz/-e/7+6sw siy4*msu)erage of the object's initial and final velq -je6sk/ s+s*4y gudko / bnwi78sm)zocity?

  Objects A and B both start at rest. They both accelerate at the same ratew9h (wcwd7i. nyq hpd ty0/h.:. Howevw.:.qh 09y7 twdy ihwch(ndp /er, object 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 from rest. They both accelerate at t 8u59 n2vsii3 le*qgjwhe same rate. However, object A accelerates for twice the time as object B. What is the distance traveled by object A compared to that 3niulij82vw s q g*95eof object B?

  When an object is released from rest and falls in the absence of friction, ws j2c4swuo* 77 xyxb/ihich of 4s77b/2s j uxcyw*io xthe following is true concerning its motion?

  When an object is released from rest and fatj4pa 95ve*b olls in the absence of friction, which of the following is true conce*po batj 549verning its motion?

  Suppose a ball is thrown straight up. Make a statement about the velocity anlb crq-j5pds;r ;w y//d the acceleration when the ball reaches the h/brj/-sp; w; l r5yqdcighest point.

  Suppose a ball is thrown straight up. What is its acceleration just before ir:ybn vwu. t(ui7 o0o )bg8(mat reaches its highest poin m ouvbo7a:tir bu n.0g()w8(yt?

  Suppose a ball is thrown straight up, reaches un4hw(()0bjr:r;afcoary 5qa maximum height, then falls to its initial height. Make a statement about the direction of the velocity and acceleration as the bal0rufyna5 )a;j b:wc( h4rrqo(l is going up.

  A ball is thrown straf96 cxch0:i6lvokj):dd xtm ;ight up, reaches a maximum height, then falls to its initial height. Make a statement about the direction of the velfj;9ktx d6ohdvx:cl :m 06i c)ocity and acceleration as the ball is coming down.

  Suppose a ball is thrown downward in the absence t/g+z4g mftgfy.dtt 7vq0m; 0of air resistance. Make a statement concerning its acceleratiz.g t/ mt47v0gqt m +g;tdffy0on.

  Suppose a skydiver jumps from a high-flying plane. Whatk/ z3p9.;l:nzrqi rf gx-c2mzpv6kt0 is her acceleration when shei;v.0p-g fx qzrp2mrznl k69:k/tc3z she reaches terminal velocity?

  A ball is thrown vertically lp.jd/x0l j: iupward with 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 til p/.j xi0dlj:mes higher does the second ball go than the first ball?)

  Ball A is dropped from the top oc cef)3ma 7e4if a building. One second later, ball B is dropped from the same building. As time progresses, the distance bet4mf7aeeci)c3 ween them

  Ball A is dropped from the top of zend6z/4s s3fa building. One second later, ball B is dropped from the same building. zezns3 s4f6d / As time progresses, the difference in their speeds

  Two objects are thrown from60d: ga3v jywn the top of a tall building. One is thrown up, and the other is thrown down, both with the sa j3gn6dvwy a0:me 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 straigrur43 (kq:ztmrq,i9d n 4drx8 ht down from the same building. They are released ar r9dn mqkdr8( q r,u4ix4:tz3t the same time. Neglect air resistance. Compare the accelerations of the two bricks.

  An object is moving with constant non-zero velocityq39:7)wo v j xzqljd+s in the +x axis. The position versus time graph of this objz: 7vw9dojj +q)xq ls3ect is

  An object is moving with constant non-zero acceleration in the +x al 3-z* g+5 m ech/q(/iojxdeguxis. The position versus time graph of tho +izele xq5cm/uh/3*dg(-jgis object is

  An object is moving with constant non-zero velocity in the +x axis. The velocnn;4+usnyti7 ity versus time graph of this object 47usn;nniyt+is

  An object is moving with constant non-zero acceleration in the +x axk0i o.oqnj0/z is. The velocity ver.i zj0/ko nqo0sus time graph of this object is

  The slope of a position versus time graph givesi h 2*nfww.1og7gt m*rft3p(p

  The slope of a velocity versus time graph give .a vhbhf,5ie)s

  The area under a curve in an acceleraqeet)v6 sr aa iqqy4m ; *i9x8q:ro/h:tion versus time graph gives

  The area under a curve in a velocity versus time grapb)lc813ic h m:hgfgh)ee x.xu)o 2g z.h gives

  If the position versus time graph of an object is a horizontal8xpspdu ,4x9oase (1 zn37d eu line, the object iz89x(,s4 due1spn u7d oa x3pes

  If the position versus time graph of an object is a vertical line, the x: xt+o6k h8yqobject ishy6q8 +txxko:

  If the velocity versus time graph of an object is a horizontal line3ss9t,, ojvtf, the object s s,tfot,93jvis

  If the velocity versus time graph of an object is a straight k+e sc9lm4w+w line making an angle of 30 degrees with tscwe +wk+l9m4he time axis, the object is

  An object moves 15.0 m north and then 11.0 yhe vlp trj9* :4ah8nvmhryxz47 *75y m south. Find both the distance traveled and the magn4j hx*l: 9 r7paehym4*5yr vyhzvnt87 itude of the displacement vector.

  A boat can move at 30 km/h in still water. How loffkm ek rqbo732qx0: /ng will it take to move 12 km upstream in a river flow230q qekr7/f:f kxombing 6.0 km/h?

  55 mi/h is how many m:sce+:097 g7fp5uqyvd zo zps9a wn+l/s? (1 mi = 1609 m)

  What must be your average gav(kpy )+2x q wbq 75iqkm:d4speed in order to travel 350 km in 5.15 h?

  A runner ran the marathon (approximately 42.0 km)vge vhbl8q4fj3 ;g2plr 38e.o n, w,jzbq*qg0 in 2 hours and 57 min. What is the avera l20 jrp.n b3,v8b,8qfq4qgjg*z;3hlgov e wege speed of the runner in m/s?

  A car travels 90 km/h. How lo)3u j ple7aiwvg r24l(ng does it take for it to travel 400 km?

  A ly (light year) is the distance that light travels in one year.i,/dxr9ihzxy 8 +fx, h The speed of ligdr fh+ix xxzyh9/,8,iht is $3.00 \times 10^8 \; m/s$. 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 jt 41 ork)a*kv*2wmt nto the side for 4.0 s, howvktkmo *2t1wrj)n 4* a far do you travel during this inattentive period?

  If you run a complete loop around an outcwsl5lip t,l *i a,k/9door track (400 m), in 100 s, your averagl a/ wc,i 5,lktsi9*ple velocity is

  A polar bear starts at the North Poo/ *wv :bcco4+v96nn7ztefs ble. 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 min.efb/ n6c*+ vtonsc 4vozw b97: What was the bear's average speed?

  A polar bear starts at the Nor1tzi3 pv6x,q i4h7o anuuo9 4wth 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. This trip takes 45 min. What was the b7tihq,14aw34 pv9 uox 6ziunoear's average velocity?

  You are driving home on a weekend from school at 55 mncviqc8dp j *t(x+3/ri/h for 110 miles. It then starts to snow and you slow to 35 mi/h. You arrive home after driving 4 ho3nxp(dt+j/ 8r * iccvqurs and 15 minutes. How far is your hometown from school?

  A motorist travels 160 km at 80 km/hc ruz)l2mxb660x .q xd and 160 km at 100 km/h. What is the average speed of the motorist for thi2x0). 6 m6zrxxuldbqcs trip?

  A motorist travels for 3.0 h at 80 km/h and 2.0 h at 100 km/h. Whjb1vu3w,6z7zmfk pl i0v; 8ntat is her averag 6vfz j 38uwlmb;,i17ktn0zpve speed for the trip?

  An airplane travels at 300 mi/h sou 9r*mvdtkfjq gq2 q-u *hd:5r+th for 2.00 h and then at 250 mi/h north for 750 miles. What is the average speeduf95 jh qgq*rkr2v*+ -tdmqd : for the trip?

  In a 400-m relay race the anchorman (the person who runs the last 100 m) for teavbx8q3)hf /lny0t s2dm A can run 100 m in 9.8 s. His rival, the anchorman for team B, can cover 100 m isq h 38l)0/xfbnvy2dt n 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 a stor 20t s8:ptikap after 10 s. The car's average velocity during de:k8a20pti strceleration was 49 km/h. What was the car's deceleration while slowing down?

  An airplane increases its speed 4.jz, 2nzob27uqzxqk from 100 m/s to 160 m/s, at the average rate of kjz.zq2 n7 oq z2x4ub,$15 \; m/s^2$. How much time does it take for the complete increase in speed?

  A car traveling 60 km/hdwfk m(bwkt65-d44q a 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 acceleilfxwv 97wv4* f6/bohrates 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 constm vjod.7k24oeant acceleration ooomj2 7ev4 kd.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 4.8 m/s experiences a )mr1lil2wsja4s kd ; h34e)lzvlc;o1constant acceleration of1z w osljdrkle2m)vh1 ;l)4 3;4c lais $4.4 \; m/s^2$. What is the cart's displacement during the first 5.0 s of its motion?

  A bullet moving horizontally to the right (+x6k5xt90lfzrl p er+2 c direction) with a speed of 476 m/s strikes a sandbag and penetrates a distance of 85.52 cm. What is the average accelpkl+ r5z c re09f62xtleration, in $m/s^2$, of the bullet?

  A jet fighter plane is launched from a catapult on an aircraft carrier 7jg0us/9x fcr. It reaches a speed ocx/f7j 9usr g0f 42 m/s at the end of the catapult, 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 acceleratiqevdzsd* hnr++a):7 7 kjms)at /r9a7rhms2ion 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 ohokpr+h(y 42 btir,jp qn2zuv 0 -4ge,f 200 m. What is its average acceleration?2ng jpb,i+20(4z4roerhpukt y,hv- q

  An object starts from rest and under2i*a z4i7rxxpb f egk22xs06t+,ewytgoes uniform acceleration. During the first seco*x6p 2z0iax 7f ytxtgrs k+e,bi2e2w4nd it travels 1.6 m. How far will it travel during the third second?

  An object is moving in a straight line with constant acceleration. Initially ii7 mya4 auyku;8.,*vp mf piv0t is traveling at 16 m/s. Three seconds later it is;,av0pi ukpyiuf7m.*m y v4a8 traveling at 10 m/s. How far does it move during this time?

  A car starts from rest and accelerates 3(gx,uyw nu l9uniformly 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 caf6/cid (ukz 0sn 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 d8e j6a) gzrvas8(hn8that has been waiting at the intersection star6hg)ez vn a88sj(8d arts 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 wr-o2a6my g k gzeg7 (ccv,bg6+ith a speed of 12 m/s on the surface of planet X where the acceleration dgkr2 +,c67y bg(gz- gvc6oma eue 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 u7 b;.u0 iqfi*tj nix; c8h;qts3 u+bj12 m/s on the surface of planet X where the accelertbtij0is8q*n x;fq. j;; u+ ciu73hub ation 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 upward with a speed of ju,nj7,hp7iut* 7cry 15 m/s on the surface of planet X where the accelerap*7 c,rjtujyn 7iu,7htion due 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 ub0 4 c9-8rfaajcg,pz2rqt lv3 pward with a speed of 14 m/s on the surface of planet X where the acceleration due b jgar0trvc2 9c4 qf 3-l,apz8to 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 friend holds a ruviwz2w iwfzfq,15 /e2ler between your fingers and releases it without warning, how far can you expect the re v2fwz5i/, 2wqi1zfw uler to fall before you catch it?

  A ball is thrown upward at a velocity oa5, ki m(i9ibsz9fhbk lo+8c(f 19.6 m/s. What is its velocity after 3.0s +ca ,lbi zh(9imb oki(f589k0 s?

  A bullet shot straight up returns to its nb bp0kg*4r8a gcl-)vstarting point in 16 s. What is the initial speed of the bullet? )p8nc 0v4ar*bgblg-k

  A ball is thrown straight up withig)q uj0jlmhg4 r4il ye ie(/*b)/7 ga a speed of 36.0 m/s. How long does it take to return to its )4ijg(7qe4ju0 mabr* / egihgl )/yilstarting point?

  A ball is thrown downward from the top of a building with an initial rz+/x3;r ,j ez (yu*augp n9egspeed of 21 m/e xg* ,rjugzpnz;(/yu 3+9raes. It strikes the ground after 4.7 s. How high is the building?

  A ball is thrown straight up with a speed of 30glh9(2)m kd5jsz )9u zrvhu m: m/s. (only fill in numerical value in the blanz 9j2g)khs)5 uurl hd :vm9z(mks)
(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 speed of 45.1 m/o it2vh;b (65fs7 wfz cnf2j+. 8ocesdlno+5l 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 1 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 o1*ihvrygf x/n 5(9rg*gwdy( at t = 1.0 s?

  In Fig. below, what is the vo 9xj:kvy6 +myelocity at t = 2.5 s?

  In Fig. below, what is the vel9atc(3qjk7q- p.ypw eocity at t = 4.0 s?

  In Fig. below, what is the vgly0h* *h;hzn-q2lv 3 pbic. aelocity at t = 5.5 s?

  In Fig. below, what is the average velocity from 0 to(gi q(fd-iqk7u py0.pfc 7u2 t 4.0 s?

  In Fig. below, what is the average velociirt2 y4 tkibvwyu 6+o -v*2q7pty from 0 to 6.0 s?

  In Fig. below, what is thnorv z9ni qzoc19n:94e acceleration at 1.0 s?

  In Fig. below, what is the accelerati/yk9it04 0vr1 zr 2daqx 4pgwzon at 3.0 s?

  In Fig. below, what is the averag z9.cp.a;p9rn:c9 rq g)bn wvne acceleration from 0 to 5.0 s?

  In Fig. below, what is thfe(s z45yn y 2cp/k6 fvp36dvde average acceleration from 0 to 8.0 s?

  In Fig. below, what is oqycyk*co+xr gt97mfpw(3r/ noa ,.1 the displacement from 0 to 8.0 s?

Does a car speedometer measure speed, velocity? {spee-ledzo b83w. e-hztd2d|velocity}

  An object can have a varying speed if its velocity is constant.4.bf tx1qcyi/

  The velocity of an object can be negative when its acceleration is positiv:gyr 1yurv8 u.vnb)0f e.

  If one object has a greater speed than a second object, the first must havr;q 3;o ; g j+cb/xkf*hc;t:tb po:kgje a greater acceotc3 ;jhqj; ckfo;pk+tr::/;gbg x*b leration.

  Two cars emerge side by side from a tunnel. Car A is traveling with 17anlufqv, b8(:d pkpw.q rn *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 increa+ s jdb18ta8gbsing in speed as its acceleration decreases.

  A baseball player hits a foul ball+ b7r+wivxron n x,m.eu+: wy- straight up into the air. It leaves the bat with a speedm-w7:r n.by+x v+oi r,xuwe+ n 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, whaqjy1* .lg (arc*tszo:t is happening to its acceleration, how does it change if air frict*qacgtz s.lo1jr (* y:ion is ignored?

  As a freely falling object speeds up, what is happening to its accela wgq* ol s9sxwx:a5t./ ixi39eration, how does it changw*oxaqi /l99 x3s:aw.5gs itxe if air friction CAN NOT be ignored?

  An object that is thrown ve jmo2kera. sci7 o*pq ;*c99mortically upward will return to its original position with the same speed as it had initially if air resistance is negligible. If air resistm2c9a qs9opmk;ji7o * or*.ec ance is appreciable, how will this result be altered?

  An object can have z hx*4yn)ksdpqq3 vi8xn4 ge/0ero velocity and nonzero acceleration at the same time.

  An object can have nonzero velocity and zero accelerati2:z0b496h 9alzdvc07jrwuoii - wv buon at the same time.

  An elevator moving from the second floor to the fifth floor making nojyp:xz2+,rg nl/q j2 ,pj q4as stops along the way has zero acceleration all the tqgjn 4+ j ,qz:/p,2y2sl ajrxpime.

  A rolling ball movessjjelemg 9s9/8 1rpu 9y,fmb6 from $x_1=3.2 \mathrm{~cm}$ to $x_2=-6.0 \mathrm{~cm}$ during the time from $t_1=1.8 \mathrm{~s}$ to $t_2=5.1 \mathrm{~s}$. What is its average velocity?  (数值)  $cm/s$ (only fill in numerical value please)

  A particle at $t_1=-3.0 \mathrm{~s}$ is at $x_1=2.1 \mathrm{~cm}$ and at $t_2=3.4 \mathrm{~s}$ is at $x_2=8.3 \mathrm{~cm}$. What is its average velocity?  (数值)  $cm/s$

  A person jogs eight completenxjbvc 3cvxy0obp1 4:a98f2v laps around a quarter-mile ($1 \; mile = 1609 \; m$) track in a total time of 10.7 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 91 m ( dym uq6myvgjs*s n lb0df.d:rl4,876c.ei j away in 12.m 0j. dudsd,8( : *flcq.b7m6syrengyvi4l6 j1 s. It then turns abruptly and gallops halfway back in 4.6 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 fro+l1guh8g7 d5 bob0y vfm $12 \; m/s$ to $22 \; m/s$ in 4.7 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 frops2 dtcq+-8oq m $22 \; m/s$ to rest in a distance of 74 m. What was its acceleration, assumed constant?  (数值)  $m/s^2$

  A light plane must reach a speed of (3x e c, erjyn8,8jmnj$28 \; m/s$ for takeoff. How long a runway is needed if the (constant) acceleration is $2.5 \; m/s^2$ ?  (数值)  $m$

  A world-class sprinter can burst out of the blocks to essentially top speed2cae.mi4 p j0k+w znzgpm +f-. about mzg+iw -kjz24n 0fp.c e pma+.$10.6 \; m/s$ in the first 14.8 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 frojjd 4xl 9oe9llwq,+i j6ya;c9m a speed of $20 \; m/s$ to rest in 4.30 s. How far did it travel in that time?  (数值)  $m$

  In coming to a stop, l ::a.cu;eltpa car leaves skid marks 92 m long on the highway. Assuming a deceleration o :clt:u .epal;f $7.00 \; m/s^2$, estimate the speed of the car just before braking.    $m/s$

  A car is behind a tru-ba,ti;wef x:ck 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).    $m$