Suppose that an object travels from one point in s,qaxm31p 8bcjpace to another. Make a comparison between qx bjmp 3ac81,the displacement and the distance traveled.

  When is the average velocity of an object equal to thdy 16 n+ta9n dcmu23suw62 avle instantaneous velocity?

  A new car manufacturer advertises that t nwedt8y9g kftuj0*k0n-.*yuheir car can go "from zero to sixty in 8uk-09*fn .8yu jegw0yntdt*k s". This is a description of

  An object moving in the +x a)tr; +wz :lqdxqpa 54c iw4vb:h(6slaxis experiences an acceleration of $2.0 \; m/s^2$. This means the object is

  Suppose that a car traveling to the Eay +tes/bfqx zmpiva850- )h7s st (+x direction) begins to slow down as it approaches a traffic light. Make a statement concerning ih /vqxf7zm08eays)-+pt b 5sits acceleration.

  Suppose that a car traveling to the West (-x direction) begr9mt xp9b:mjj825hpfg+ k2w2r)ikye ins to slow down as it approaches a traffic light. Make a statement c me5 k 9pxwbi j:y22rrpg28jh+)tfkm9 oncerning its acceleration.

  Suppose that an object is moving with a constant veloxb z;gu0p tdwhq)5(+wcity. Make a statement concernih(wqw z0+pgubx; d5)tng its acceleration.

  If the velocity of an objecfxo-7j8rlo2:g +ls irt is zero, does it mean that the acceleration is zero? Support your answer with an e2+fr : osoxl7ij-r8 lgxample.

  Can an object's velocity change direction when i: mtnp4a: y3jb( +ajfhogo :q0ts acceleration is constant? Support yjmpq(+foa0t3 ::4b njo:ahgyour answer with an example.

  Suppose that an object is moving with constant acceleration. Make af( fo9q;:x3ipc l/en ivpd:5 a statement concerning its motion with respect tla:vnciq3 fxp; d5pefo/( : i9o time.

  Can an object have increasing speed while its wx;g isz)4* waacceleration is decreasing? Support your answer wa *igxw4s;)z with an example.

  Suppose a can, after an initial kick, moves up along a smooth hill of ic4lsd2j g ;n1p y,pkr-ce. Make a stateme;2 cgpns, prklj4 yd1-nt concerning its acceleration.

  Under what condition is average velo b19duuoo2bhm;vie/,: v 7 c;b au/fazcity equal to the average of the object's initial and final veluvu :i7zhabbob2/cevf uo,9m; d;a/1ocity?

  Objects A and B both start at rest. kr5uxt qpko. hmy20 1v7fa, ntbj7x( + They both accelerate at the same rate. However, object A accelerates for twice the time as object B. Wha(q7p t7 ra5bu mk kx,x+f ytvj2hno.01t is the final speed of object A compared to that of object B?

  Objects A and B both start from rest. They bothk1;d-yp vd)bkt )n1h ezze,n) accelerate at the same rate. However, object A accelerates for twice the time as object B. Whaz e)-1y p);kdzv1 dkt,bn)enht is the distance traveled by object A compared to that of object B?

  When an object is released from rest and falls in the absence4 bxfd:i2inqz:3+r ap of friction, which of the 3:nbp 2xa4rdq zi+:f ifollowing is true concerning its motion?

  When an object is released from rest and falls in the absence of friction, whi2 ifr, ;9tyaoo7f1jiach of the following is true concerning itsi,yf7t2i a;rj aof 19o motion?

  Suppose a ball is thrown strad* +.b1mrm pk*be.fqop; liwt01ft0i ight up. Make a statement about the velocity and the acceleration wheibit+q .bfd**mwkp e1; l10pmor.f0tn the ball reaches the highest point.

  Suppose a ball is thrown straight up. What is itk f-tyhw;z 4p/ shs0b ;sbj(v2s acceleration just before it reaches its b zf tv(ks;;shjpsy/4hw- b20highest point?

  Suppose a ball is thrown cprfrn5idk4(r6 v2 -ustraight up, reaches a maximum height, then falls to its initial height. Make a statement ab2udnp 6-5rrv 4f c(rkiout 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 its invwug4 sv 7b)(nitial height. Make a statement about the direction 4ung7v(wv )bsof the velocity and acceleration as the ball is coming down.

  Suppose a ball is thrown downward in the absence of air resistanc99ap4(5xz ntrqqyc. +lu lm5n e. Make a statement concerning its acceleratl+t4rynlqcpu995 . zaxq5n(m ion.

  Suppose a skydiver jul78gfub5 6 ;rz03yj k3cijrfrn36ucw mps from a high-flying plane. What is her acceleration when she she reaches terminal r g7brjr5u68cjln0k;363wicff u y3zvelocity?

  A ball is thrown vertically upwar bit6jid;16ix0lwh.o ) / rhrqd 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 hh rlrqji;.)o1bdt 0/6 iiwx6 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 from4r4zv;oq enqg8 s5/k c (8olf7k*nejw the top of a building. One second later, ball B is droppe k l5qe*jzf;rcg47 4n/8qskn(8oovwed from the same building. As time progresses, the distance between them

  Ball A is dropped from the top of a building. One seconm 9db6ki5wzs1d later, ball B is dropped from the samesd965mkw1ibz building. As time progresses, the difference in their speeds

  Two objects are thrown from6ju;s(t p uskqdrc5*g3(.uyj the top of a tall building. One is thrown up, and the other is thrown down, both with the same initial speed. What are *yu(qj ju g cd(upt.s;sr635ktheir speeds when they hit the street?

  A brick is dropped from the top of a buildinau28xm rxt84jg. 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 brickxj 4ux8t2ra m8s.

  An object is moving bf(xx:cc4p q3with constant non-zero velocity in the +x axis. The position versus time graph of this object isq43 f xcb(:xpc

  An object is moving with constant non-zero acceleration in the +x nol*m); agvm3* j5dz oaxis. The position versus time graph of this object i;jmv*nd mgl a)o53*ozs

  An object is moving with constant non-zero velocity qmpsdri sfyn 4s(iq 2b((1h69in the +x axis. The velocity versus time graph of thiqf(msi6nisb r9(h4yd1 p2s (qs object is

  An object is moving with constant non-zero accel9:rr9il, gs ,pk-bp nperation in the +x axis. The velocity p r-:r,p, k9i9lns pbgversus time graph of this object is

  The slope of a positiop cgcf+ -xm -ikot9q*7n versus time graph gives

  The slope of a velocity q*apg: (tazx,apgq -8 versus time graph gives

  The area under a curve i0/w 13 lqqypsl6l+m-5 p gyz 7r jcyy3q,lz9egn an acceleration versus time graph gives

  The area under a curve in a velbtb(y +.ru;k3 xvfs /uocity versus time graph gives

  If the position versus time graph of an ob)azgga d42q0/ aw d;ytject is a horizontal line, the object i4a yw;g qagd/02)datz s

  If the position versus time graph of an object is a vertical line, t :h2fev .3soqjc qk 7o*+z-hbrhe object isz+v3oh2o 7rc- k .*b:eqjshfq

  If the velocity versus time graph of an obje bav.q:88nseg jv *3hrct is a horizontal line, the object ishqjvgs3 : r8a*8.benv

  If the velocity versus tq y0q ybnz;7y)g,kvl0ime graph of an object is a straight line making an angle of 30 degrees with the)qv;g yzq7n ky0b y,l0 time axis, the object is

  An object moves 15.0 m north and then 11.0 m south. Find both the dist f,/l4fu,opa5qiw 2 m u,dzz;wance traveled and the u;,,/z 4,wafoumqpw 2zli 5dfmagnitude of the displacement vector.

  A boat can move at 30 km/h in still waterlz,w(3cm1o- slmp okkh: 13kr. How long will it take to move 12 km upstream in a p lro-1hk3lw:m3ks(, k zm 1coriver flowing 6.0 km/h?

  55 mi/h is how many m/s? (1 mi = 1609 m)9jb bkx 44rfv/vx8jo9

  What must be your average speed in order to travel 373zke5 qaix9k50 km in 5.15 h?

  A runner ran the marathon (approximately 42.0 km) in 2p 3xh0sk8 +udn hours and 57 min. What is the average speed of the runner d nukxp3h0s8+ in m/s?

  A car travels 90 km/h. How long does it take for2wr9j+jm9zs8w;re yo1/10 hgj uhh lj it to travel 400 km?

  A ly (light year) is the distance ia wa+x6aldv67 7 r;hithat light travels in one year. The speed of light iw i lhi;a+67 rdx76aavs $3.00 \times 10^8 \; m/s$. How many miles are there in a light year? (1 mi = 1609 m, 1 yr = 365 d.)

  If you are driving 72 km/h alic umg h*g* w)z2vt43qong a straight road and you look to the side for 4.0 s, how far do you travel during this inattenc 2uzwh)*3 4vq*t ggmitive period?

  If you run a complete loop aroun2v kv (ne7b7atd an outdoor track (400 m), in 100 s, your average velocn a2tkbev77( vity is

  A polar bear starts at the North Pole. It trb6 yfz)f/osa yj4-wu7avels 1.0 km south, then 1.0 km east, then 1.0 km north, then 14yf-j yu 7)6fzwab os/.0 km west to return to its starting point. This trip takes 45 min. What was the bear's average speed?

  A polar bear starts at the North Pole. It travels 1.f758i3r5cu(36 3 l fjp rpqlae) xfglqzl;il/ 0 km south, then 1.0 km east, then 1.0 km north, then 1.0 km west to return to its starting point. Thi3pqx fli ecq7j 8lfa)r 3u r(/ f6;zli35l5plgs trip takes 45 min. What was the bear's average velocity?

  You are driving home on a weekend froqz6 es5h:u( zx: lidy9m school at 55 mi/h for 110 miles. It then starts to snow and you slow to 35 mi/h. Youzuqs(:l 9 h6y:i5e dxz arrive home after driving 4 hours and 15 minutes. How far is your hometown from school?

  A motorist travels 160kbcl :*b uuo8bg,s5 t3 km at 80 km/h and 160 km at 100 km/h. What is the average speed of the motorist for t kgs85u*l 3bbu:bcto,his trip?

  A motorist travels for 3.0 h at 80 km/h and 2.0 h at 100z -mv(qpm ju2e(p cu4* km/h. What is her averagpv j4 -(e( uuzqmcm*2pe speed for the trip?

  An airplane travels at 300 mi/h souof5lg -trfedr*220wlth for 2.00 h and then at 250 mi/h north for 750 miles. What is the average speed for the tr twle-d5of l2*r0g2 frip?

  In a 400-m relay race the anchorman (the person who runs the lastgj 2 83an/ctms 100 m) for team A can run 100 m in 9.8 s. His rival, the anchorman for team B, can cover 100nm2gsj/ 83t ca 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 a stop after 12 s. The car's average vom (qzt .pmk+v0qig :6xai1k* elocity during deceleration was 32 km/h. What was the car's deceleration while ia*1gp0.+okm6m:( i vkqqtz xslowing down?

  An airplane increases its speed from 100 m/bi:(:t gs:k ams to 160 m/s, at the average rate of k::a(m :s bgti$15 \; m/s^2$. How much time does it take for the complete increase in speed?

  A car traveling 60 km/h accelerates at the rates snpilx a m22b 4re3ae557(ei 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 accelerbi; 8 pma8w0gspoi,:lates 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 cy4 nihzvf3 q9 -l0ifd(onstant acceleration i0df 9lvy 3ih fzn-q4(of $2.0 \; m/s^2$ for 15 s. At the end of this time, what is its velocity?

  A cart with an initial velocitzfikt 1v : kq+s92zn0.2m.rivbzany; y of 1.9 m/s experiences a constant acceleration o2m:vz1 knzz rvqna.;y i9.fs 0+btik2f $2.8 \; m/s^2$. What is the cart's displacement during the first 7.9 s of its motion?

  A bullet moving horizontally to the right (+xpda(:ifw vaiq.9qo-5o -y;qz9sj2 e j direction) with a speed of 286 m/s strikes a sandbag and penetrates a distance of 40.79 cm. What is the average acceleration, inf5ze: .j-qaii(v-j2pq s 9 o;odqya9w $m/s^2$, of the bullet?

  A jet fighter plane is launcw3gu (e +cv7aybozkdie .(9ppj. ,v.w hed from a catapult on an aircraft carrier. It reaches a speed of 42 m/s at the end of the catapult, and this requires 2.0 s. Assuming the acceleration is constant, what is the lozk cba,.(7pw(.ivwy .p9d+ueg 3jveength of the catapult?

  A car starting from rest moves with constant accelerc9m ttq + )vbs t7jiofj2e .sucuc10)7ation 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 average act)qzru3vi z6. e treo:y w/(-anfi96a celeratnz-ifrva r/ytu.) 366zaeq( e t:i9owion?

  An object starts from rest anp ,i0l z7 jse.ilkag6;,kg7y itmn3i -d undergoes uniform acceleration. During the first second it travels 8.0 mige;6pi0yk7l i,jtin z7 3-kas , ml.g. How far will it travel during the third second?

  An object is moving in a straight line with constant 9;y7. gbxn6igieim 7 iacceleration. Initially it is traveling at 16 m/s. Three seconds later it is traveling i i7y7ebgg i6m. ;9xinat 10 m/s. How far does it move during this time?

  A car starts from rest and accelerates uniforml9 qhmdutui 9jp.72 1s o +fn/7yqwhk,oy 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 rkk+(xi- 3rr jidsg(lt6:d) sb oad 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 traffscg+/0m7 ujw*6 udcw stu. b(lic light turns green, a car that has been waiting at the intersection starts ahead with a constant acces (wmd j7.0t6b* /lgw+uucsucleration 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 m/s on the surface of uqjiz y+1wj1no 2 pm6raz29 l0planet X where th6ojz z2yrpju011ilwnqm a +2 9e 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/s on gv1 df)+ru e,z,e-w ooo aiy3)the surface of planet X wherev,o-,1oa))+oeizgrw eu f d y3 the 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 upward with a speed of 15 m/s on the surface of planet u(fp i-y1l* keX where the l*iyf epku1-(acceleration 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 upward with a speed of6 pr++k (lf.)w2ep4mivg axyf 14 m/s on the surface of planet X where the acceleration dufp24a(i +6xmf.ypevw gr ) k+le to 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 x sycd7 0-0*a7doym eoholds a ruler between your fingers and releases it w0o*ody axs 7e0y-d7 cmithout warning, how far can you expect the ruler to fall before you catch it?

  A ball is thrown upward at aud ylv95h-l2fduc t h 383n4 9s)zdgh (qdk(eb velocity of 19.6 m/s. What is its velocity after 3.0t vddfn-zh35kydl ehl3c4q9ds 9u8h(g)( b2u0 s?

  A bullet shot straight up returns mhr)b:2z c8 j bey(p1pto its starting point in 10 s. What is the initial speed of the b)(chpre 1y 8b2mjzpb: ullet?

  A ball is thrown straight up with 9b5p5l emy 91ohkk*3 rveeax 7an3t/ta speed of 36.0 m/s. How long does it take to return to its starting po79hal 53t mne*ep5bkto1yv k/a r3x9eint?

  A ball is thrown downward from the tonasa 0th r-tal q6n5*1jolzo),d3r5o p of a building with an initial speed of 19 m/s. It strikes the ground after 5.7 s. How high is the t0qoza lonn r -1*o 5t5,ahasjd36r)lbuilding?

  A ball is thrown straight up with a speedlie: ni/zj-2r2i cls u4rc,)k of 30 m/s. (only fill in numerical value in the blanks) 4sei zrn22jlruc ,)i :/-cilk
(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 ryv y79)q-jd rbp2pm8of 47.1 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 3 seconds later.  (数值)  $m/s$
(e.) Determine the time at which the ball pass a point 7 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 7.0 m above the point of contact a second time.  (数值)  $s$

  In Fig. below, what is the velonpolfyt6. 7p* +sda -bcity at t = 1.0 s?

  In Fig. below, what is thpw7o9/i2 r zyzf8 jxc4e velocity at t = 2.5 s?

  In Fig. below, what is the velocity at.m 9r56xej1 chsrq7gx t = 4.0 s?

  In Fig. below, what is the velocity at tdq - )zlg-usp le:j9e7 = 5.5 s?

  In Fig. below, what is the averbt 49d9t rtohfrww.:sr b+ k+;age velocity from 0 to 4.0 s?

  In Fig. below, what is the average velocity fr80tyw, b d +e0af-dlz-1w dfuxm7p(x rom 0 to 6.0 s?

  In Fig. below, what is the acceleration at 1.0 sydatcx6ex03shfaw 2 ( 63t i-s?

  In Fig. below, what is the acceleration at 3.0 s:cdcgki1c5 lr/ c 65jrts;sb1?

  In Fig. below, what ih h50sn 5(zptgs the average acceleration from 0 to 5.0 s?

  In Fig. below, what is the average acceleration from3npq)w i8l ;jkb94qdm 0 to 8.0 s?

  In Fig. below, what is the displacement from6b- fttb2 qu;t/ :g 9sjwzgd4s 0 to 8.0 s?

Does a car speedometer measure speemc5ktdmeom*85)s(j i d2 lbzc 9b-po5 d, velocity? {speed|velocity}

  An object can have a varying speed eer v5.3t5lem if its velocity is constant.

  The velocity of an object can be negative whemb.eb+:t- tu pn its acceleration is positive.

  If one object has a greater speed than a second object, the first must have a get0akg;;-/ xz 1ls tagreater a-eka ;xst1z al0gtg/;cceleration.

  Two cars emerge side by side from a tunnel. Cr sdjyi* 3n08aar 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 ar18n8 xyi514 yu z esz9nr99xt;sa hdds its acceleration decreases.

  A baseball player hits a foul ball straigh:qxcv)2 -( blrbfxiv ,t up into the air. It leaves the bat with v,b)bix(2r- lqvxf c: 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 o4r9z6by54qwyb6dh p3jn qe-e bject speeds up, what is happening to its acceleration, how does it change3eej6-q n4pr 4b5zhy9qdw6 by if air friction is ignored?

  As a freely falling object speeds up, what is hap-nft(1ydlz ird :xj)), h/qr vpening to its acceleration, how does it change if air friction CAN NOT be ignored?,(1q rfj) :dy) hl -zr/dvxnti

  An object that is thrown vertically upward will return to its original positio:j(c gm6da n stoar-34n with the same speed as it had initially if air resistance is negligible. If air resistance is appredca4tr-os( :m anj 6g3ciable, how will this result be altered?

  An object can have zero velocity 7jgui 0u3hc-fand nonzero acceleration at the same time.

  An object can have nonzero velocity and zero acceleration at the sai0 9 qo :8xt)y z*vljj4emu .mbdjoy;*me time.

  An elevator moving from the second floor to the fifth floor making no b yu(f qil80*qstops along the w qiq(l0*b8yufay has zero acceleration all the time.

  A rolling ball moves -yv(t mwns7;r( ay dmr 44l5w8i a4ffifrom $x_1=2.1 \mathrm{~cm}$ to $x_2=-8.0 \mathrm{~cm}$ during the time from $t_1=1.7 \mathrm{~s}$ to $t_2=5.0 \mathrm{~s}$. 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 $x_1=2.5 \mathrm{~cm}$ and at $t_2=4.2 \mathrm{~s}$ is at $x_2=8.4 \mathrm{~cm}$. What is its average velocity?  (数值)  $cm/s$

  A person jogs eight complete laps around a quam/ qwh yz.du.4rter-mile ($1 \; mile = 1609 \; m$) track in a total time of 8.4 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 strak/q198buy)e m9x*f slge hph ja)9k3w 34zrizight line, moving 108 m away in 13.5 s. It then turns abruptly and gallops )xkju*1i3 9b /mhferw )z9gakz3leyhp89 q4s 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 fromr tgqp*f-i.ihjcu bz y(w ;544 $11 \; m/s$ to $24 \; m/s$ in 5.4 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 -wq y j/py,: z8lorabne:q((s $20 \; m/s$ to rest in a distance of 57 m. What was its acceleration, assumed constant?  (数值)  $m/s^2$

  A light plane must reach a speed o f .vekhgpyp9 /ucqi:5j:+d.cx;mv3 vf $30 \; m/s$ for takeoff. How long a runway is needed if the (constant) acceleration is $2.1 \; m/s^2$ ?  (数值)  $m$

  A world-class sprinter g i 0ml)45z ensmg:./c-zkx-lpy y0zlcan burst out of the blocks to essentially top speed about zn/zg 04lel-l pymikxm.5s0 cy) g z:-$10.4 \; m/s$ in the first 10.6 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 xw0e )3/msrumfrom a speed of $21 \; m/s$ to rest in 4.53 s. How far did it travel in that time?  (数值)  $m$

  In coming to a stop, a car leaves skid marks 9xvu75r sr ) gtnl-xfq/+(cuys /y3tg- 2 m long on the highway. Assuming a deceleratsnc gy g lr/-3x(tvtysr)+ u/5x7 f-uqion of $7.00 \; m/s^2$, estimate the speed of the car just before braking.    $m/s$

  A car is behind a truck goingac;l(em.z+ my $25 \; m/s$ 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).    $m$