Suppose that an object travels from one point in space :o2 04w z4um zi;egwx2 bev z;rhm5n3cto another. Make a comparison between the ezho vi2rg4:mxwzu 23wn4e;mc b0 ;5z displacement and the distance traveled.

  When is the average velocity of an object equal to the instantaneous veloco7poo;qudce 2ey*6)h5/kn:odv -sm w ity?

  A new car manufacturer advertises that their car can gobrwmi)1mfvs; )yg d.: "from zero to sixty in 8 s". Thimsd1m .wvirgy;:)f )b s is a description of

  An object moving in the +x axis experiences a m:)uh vy4qx)wwkqr7yh3z;9 an acceleration of $2.0 \; m/s^2$. This means the object is

  Suppose that a car traveling to th+vn-zn7bx3dqkm 7m th f6n20ye East (+x direction) begins to slow down as it appr0dm 7kzhyvxft+3qn7 6mn 2- bnoaches a traffic light. Make a statement concerning its acceleration.

  Suppose that a car travelv w wq.l;g-8y34ylcouejke4 )ing to the West (-x direction) begins to slow down as it approaches a traffic light. Make a statemee 4yy-. ;kvjlew3oq)g84 uclwnt concerning its acceleration.

  Suppose that an object is moving with a constant velocity. n llsm vm:8(0-(8vxiuiw)fzb Make a statement concebm- l0m ivzf:)l((8ivxs8u wnrning its acceleration.

  If the velocity of an object is zero, does it mean tcn q7y4/fi7ys h/o6gu hat the acceleration is zero?uy7ngo s/ hq4i6f c/7y Support your answer with an example.

  Can an object's velocity change direction when its acceleration is constant? Su8dp,q/a3(yntou5 e5 abke : lopport your answer ea:o/5nko (dbt5pqa3el y ,u8with an example.

  Suppose that an object is moving with constant acceleration. x*j)):3d 0jgfycf9b;zzcqn i5jq0z h Make a statement concerj)d 30hxzn;ic :y)fjz 5 qcqg0*zj9b fning its motion with respect to time.

  Can an object have increasing speed while iegu q4*3of5dh wm9: :y srr5jbts acceleration is decreasing? Support your a g3*rrdmuowq :5jh:s945yb efnswer with an example.

  Suppose a can, after an initial kick, moves up along ;4vbht16g j tfa smooth hill of ice. Make a statvf4h bg1 t;j6tement concerning its acceleration.

  Under what condition is average velocity equal to the average of the obje4x2ai n 5kb,-9qog , ggwrvg8:7ndbgxct's initial and final gv4d2qa n8gb,x-:g5kbo, 9ggxr7wn i velocity?

  Objects A and B both start at rest. They both accelerate avrk)/vqc dk p/v0;c)+ 0kvfvat the same rate. However, object A accelerates for twice the time as object B. What is the final spee)kvf+/v ) vkc; v0rvapdc/k 0qd of object A compared to that of object B?

  Objects A and B both start from rest. They both accelerate aebkxl 4o(ct fva m;(,n u0qj28t the same rate. However, object A accelerates for twice the time as object B. What is the distance traveled by object A compared 0moau k2vb,; t(48cjnf(lqxe to that of object B?

  When an object is released fzcu.1;t2 r-royhqj v)py )g2brom rest and falls in the absence of friction, which of the following is truqyy)g rpj-h2) r tcbz o2;.v1ue concerning its motion?

  When an object is released from rest and falls in the absence of fricti:+ xdj- .- wbwlmabhb-on, which of b+lwxbwm h -d-ba j.:-the following is true concerning its motion?

  Suppose a ball is thrown straight up. pyy0hppege pb70,0 ;q lebi 8- Make a statement about the velocity and the accge08ppepp l, yybbhqei- 07;0 eleration when the ball reaches the highest point.

  Suppose a ball is thrown straight up. What is its acceleration just baffl0oux 9. w;cq 1-uw:*bt;kgaj+ot7hr i4iefore it reaches its hlq0aat fo*hu7txgb-.i 14c;kri: w 9wj+fu ;o ighest point?

  Suppose a ball is thrown straight up, reap/6zs:i6j baiz 3ipgal,a82cx,nlx1 ches a maximum height, then falls to its initial height. Maksj zgzaiipp,b23 1nxa8ca/ :,l l66xie 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 hei3s2q inxvdw9 (ght, then falls to its initial height. Make a statement about the direction2d in9 xv3(wsq of the velocity and acceleration as the ball is coming down.

  Suppose a ball is thrown downward in the absence of air resistance. Make a stat)7m h6fgpp 5tpement concerpg7tp) 5p6hfmning its acceleration.

  Suppose a skydiver jumps from a high-flying pv,uxj/:w swq )e-q3i0.gd1 evll2k kglane. What is her acceleration when se 2u si-,q vvgkw0j). 3d/qw:l1k xelghe she reaches terminal velocity?

  A ball is thrown verrij*qs /nu o7cn;r7g /tically upward 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 fiji7un/o7 cn*r s;q/grrst ball? (How many times higher does the second ball go than the first ball?)

  Ball A is dropped from the top of a building. One second later, ball B is droph39 1o gr: fpb74fnwndped from th1b9pwno7nhf r :gf 4d3e same building. As time progresses, the distance between them

  Ball A is dropped from the top of a building. One second latert7lw1z dgon8( a lw:j., ball B is dropped 7.al (d:jwznwltgo 1 8from the same building. As time progresses, the difference in their speeds

  Two objects are thrown from the top/4 s edq8izh;j of a tall building. One is thrown up, and the other is thrown down, both with the same initial speed. What hi/ds 8;z jq4eare their speeds when they hit the street?

  A brick is dropped from the top of a building. A second brick is twv yl; 0v1rlb7qq:,gnhrown straight down from the same building. They are released at the same time. Neglect ai;,n0ybw v1r qvglql:7r resistance. Compare the accelerations of the two bricks.

  An object is moving with constant non-zero velocity iiohgnxc6h ej8 64 o/n+n the +x axis. The position versus time graph of this obj6ong6 +/cix4o eh8jnhect is

  An object is moving with consd5g p53f(bfzf-xp :vqv ihpjn+m/; 4ftant non-zero acceleration in the +x axis. The position vef(-:g4jbf fdp/;zx 5 5i +nvf3pqhpv mrsus time graph of this object is

  An object is moving with constant non-zero velocitcf 8shwu6nq3 5y in the +x axis. The velocity versus time graph of this ow f85us36qh ncbject is

  An object is moving with constant non-zero ac:b nko:0ebn p/celeration in the +x axis. The veloc:0bn/ ek opb:nity versus time graph of this object is

  The slope of a position versus time graph gibhktwnd :;oa; w)m z8,ves

  The slope of a velocity versu,fek i/q.4ww7 vjtw(as time graph gives

  The area under a curve in an a;tw0 e5yph8 fvcceleration versus time graph gives

  The area under a curve in a velocity versusp1g: lw;o: c-m l0ltid time graph gives

  If the position versush1rr; h:)1 tgjrr5ktu y-+kgg time graph of an object is a horizontal line, the object ty1rgg hj r:h)5rkt+ru- ;1gkis

  If the position versus time gra0vyvo15 9:u iu(sk pa (g.klxtph of an object is a vertical line, the object istu1(s gp(l9a5.o k uxyvvik:0

  If the velocity versus time 8l.gjnlg.8s )pph2iuxuy-m- graph of an object is a horizontal line, the object imnlu-.glh 2p-8) y.up 8x ijgss

  If the velocity versus time graph of an object is a0jk+*pil sd yf* x8nl; straight line making an angle of 30 degrees with the time axis, the objenildx *;pyk*jf0+ 8slct is

  An object moves 15.0 m lp*,,o6cih mv north and then 11.0 m south. Find both the distance traveled anco,vim h*,pl 6d the magnitude of the displacement vector.

  A boat can move at 30 km/h in still w y4 es3zy uu).nx0u.ewater. How long will it take to move 12 km upstream in a river flowin4n)3wz.e. x yyseuu 0ug 6.0 km/h?

  55 mi/h is how many +)pv/ *bp8kd ulonzi*m/s? (1 mi = 1609 m)

  What must be your average speed in order to travel), *9hirxvsl3wga g g8 350 km in 5.15 h?

  A runner ran the marathon (approximately 42.0 km) in 2 hours wzwami bv2c :(*:qw*vpza:0y and 57 min. What is the :wbci zwy:vz pq2(*am:wva 0*average speed of the runner in m/s?

  A car travels 90 km/h. rqwnqzp1l857rgn+woz-:o( hi+ ( hhj How long does it take for it to travel 400 km?

  A ly (light year) is the tm8 b ujzax 1)-me0i.jdistance that light travels in one year. The speed of liub z ejmj-.xt18m)ia 0ght 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 to the side forx6tj g - -;s;gcl rss:legv:fb5v5ael+xk 8s* 4.0 s, how far do you travel dtkg:cjsls6selrv vb 5l+; -e -x 8f:g g*5sx;auring this inattentive period?

  If you run a complete loop around an outdoor track (400 m), in 100 sczc6f lq8sp2xsdy* 94, your average veloci48xsd9pz6 c s2c*yqfl ty is

  A polar bear starts at the North Pole. It travels 1.0 km s9bv :+ybuewh e03qm 1south, then 1.0 km east, then 1.0 km north, then 1.0 km west to return to its starting point. This trip ta19:qemebbhs uy3+vw0 kes 45 min. What was the bear's average speed?

  A polar bear starts at the North Pole. It travels 1.0 k ( yk m)* hkrpzl0jwogl)r:8z1m 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 w*g)mrl)1hyp:krl08( jz z okwas the bear's average velocity?

  You are driving home on a weekend from school at 55 mi/sqec / mw .a1yxl9,/i2w ndxs7h 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 your hometown from scsy e wns/7dx./2w alcqi,1mx9 hool?

  A motorist travels 160 km a2sv r3+tujt z1t 80 km/h and 160 km at 100 km/h. What is the average speed of the motorist for thistv s21ut3rz j+ trip?

  A motorist travels fok*symwv l 7l+87.ckai-yd rf 7r 3.0 h at 80 km/h and 2.0 h at 100 km/h. What is her averag7dmva*f lky7ys+ikrc l7.w8- e speed for the trip?

  An airplane travels at 300 mi/h south for 2.ns *mvv h56k0r00 h and then at 250 mi/h north for 750 miles. What is the averam5kr ns6 v0hv*ge speed for the trip?

  In a 400-m relay race the anchorman (the person who runsse 6.s jpu5v+xchgeh-w8r r1 7 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 teah serwue.x1s+8jpv6h 5 -r cg7m 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 11 s54 koe,sc- m 0:ufaahb. The car's average velocity during deceleration was 43 km/h. What was the car's deceleration while slowing d 0a -uf5 mk:hec,bas4oown?

  An airplane increases its speed from 100 m/s to 160 m/s, at the avere2j)vbcqr pdqi5/pcp 5oxq;i d ,1o25age rate of b5p ,p e5c o2;qc 5)/iiqdro 1xpq2jdv$15 \; m/s^2$. How much time does it take for the complete increase in speed?

  A car traveling 60 km/h accelerates at the rate39q(di(zd,8jzu p-s 9e lnfke 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 resc7 1e53wo.u4lymy xeos5j6hst and accelerates 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 constant acce2/jiuw1e 1exy y-l c3kleration of-iyjl2 /ycke11 w3xue $2.0 \; m/s^2$ for 15 s. At the end of this time, what is its velocity?

  A cart with an initial velocity of 7.4 m/s experiences a consaw,;vy srsu 7,tant acceleration ofay7 ,,vws rus; $4.0 \; m/s^2$. What is the cart's displacement during the first 9.7 s of its motion?

  A bullet moving horizontally to the right (+x direction) with a speed o vhfviawwl+dm6yd-v wd11z , 19(vsy*f 545 m/s strikes a sandbag and penetrates a distance of 61.82 cm. What is the average acceleratio h,61 9 lww(i11ddd av*w v+syv-mfyzvn, in $m/s^2$, of the bullet?

  A jet fighter plane is at 9yvozo/r),launched 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 s9y/ ootar)zv ,. Assuming the acceleration is constant, what is the length of the catapult?

  A car starting from rest moves with constant acceleratin+e 5g(zrjv.4cjhw,j)mk;p vkb s l/*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 au5/ hx l q)9a.xguwqr9r2+tjf distance of 200 m. What is its average acceleratioh5u2 qr flwrqx+a/jxt)ug 99.n?

  An object starts from rest and undergoes uniform acceleration. w1 l2u3pm wo 6c3n7 ebnjt8vk6 During the first second it travels 67n pck mun wjoe82wv133b6 lt3.5 m. How far will it travel during the third second?

  An object is moving in a sy/k8p;*c br sntraight line with constant acceleration. Initially it is traveling at 16 m/s. Three seconds later it is ;ynk /b c*r8sptraveling at 10 m/s. How far does it move during this time?

  A car starts from rest and accel/- t;hyokd:5g(taq t verates 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 can dece qqgblyc +jb;0 b.awd7e1- 5qelerate 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 at+ti 6e4lrcsuo:x,t qo6gar u, 539g jcw0z0 rm the intersection starts ahead with a constantstj,lzc :u i4e xa+,ou0g366w0q5 gr9t romrc 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 speed of 12 m/s on the xr1n..z hrsg:surface of planet X where the acceleration due to gravity is r sz hgrx:n..1$1.5 \; m/s^2$. What is the maximum height reached by the object?

  An object is thrown upward with e69keeo 2yg 3wdh3vtp (ntp: po6q6s8di 7m)pa speed of 12 m/s on the surface of planet X where the acceleration due to gravity i336m pnh 6opyov8qkpgp72 9e 6)stet(id:wed s $1.5 \; m/s^2$. 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 i*:m 0,wx1lso m d)fm,d.gqnzid)* dfplanet X where the acceleration due to :.fdofszw,*1 qnm ) mddi*ix,dg0 ) lmgravity 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 10-gf*emt wqfspeed of 14 m/s on the surface of planet X where the accelerat-q 1ew*mfgf0t ion 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 greater than 0.x x/9*pixwybipg /iao l paj8a685j2.10 s. If your friend holds a ruler between your fingers and releases it without wa/gi.25pp b8yxiji*xw l8x /ap 6 aajo9rning, 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 velocity after 3xa *(r8uuv7 .r sta/wm.00 sta.wv sm (a 7/*8uruxr?

  A bullet shot straight up returns to its starting point in 19 s. What issx/tk;8 si ceq5oc8vn+w6b /r the initial speed of thvw6cix85r/esbk +q sct8 / o;ne bullet?

  A ball is thrown straight up with a a (odwl,dflz)( d.r g1speed of 36.0 m/s. How long does it take to return to il fw.r,dldz (g1da)o( ts starting point?

  A ball is thrown downward from the top of a bup3fur; 4p-e0bpz6 mplilding with an initial speed of 18 m/s. It strikes the ground after 4.1 s. How high is the 3epu0r;bp p-z mpl46fbuilding?

  A ball is thrown straight up with a speed of 30 m/s. (only fill inc)e3 p f:s f o-.8mghvnnw8cd3 numerical value -ch.gn 8 cfmnfdvo3s3:)8wpe 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 air with a spf ,p+r d +jnazai18-zfeed of 48.1 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 1 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 veloci7ua5g5kb0 mro +x:w b hh3yu-vty at t = 1.0 s?

  In Fig. below, what is the velocity at t = 2.5 s?yum6g u2i 9ku8

  In Fig. below, what is the velo lxwr) 0t0.t6ip xhq3mcity at t = 4.0 s?

  In Fig. below, what is apdse* +*qeb *the velocity at t = 5.5 s?

  In Fig. below, what ivm9fa 6/rthoyrp4f ;;s the average velocity from 0 to 4.0 s?

  In Fig. below, what is the average v;c2o m/6eocvx elocity from 0 to 6.0 s?

  In Fig. below, what is the acceleratw6gwy69kukh*+, q 0rbwdc u v1ion at 1.0 s?

  In Fig. below, what is the acceleration atnmc ;rb o0- awqh(kl9ulf5n48 3.0 s?

  In Fig. below, what is the average uyr/ q g+-zbsw96hc ahu/w e,(acceleration from 0 to 5.0 s?

  In Fig. below, what is the average accelebb (-uk+3p 3uev4ip; hw 6j vl6yhtyo5ration from 0 to 8.0 s?

  In Fig. below, what is the displacement froyd lue/-h*og69 1suxo m 0 to 8.0 s?

Does a car speedometer measure speed, velocitp3xk1mh+7 q.jg iyb)zy? {speed|velocity}

  An object can have a varying speed if its veloci4yj j2sf : wqds(ind2x9c i+/kty is constant.

  The velocity of an object can be negative when its acceleration is po9ph7.:ji bop usitive.

  If one object has a greater speed than a second object, the first m0eyh8c hvdt (1ust have a greater8h1 0h(yev tcd acceleration.

  Two cars emerge side by side from a tunnel. Car A is traz5pkg 6 c*zz8yveling 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 increas 6ljq1v63sy e lojc2p:ing in speed as its acceleration decreases.

  A baseball player hits a foul ball strakd99co;q;f t rv-qb- pight up into the air. It leaves the bat wkfr-;t9-c o;v9q qdb pith 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 object spb-;8po- krin :ta,f+*fg yju seeds up, what is happening to its acceleration, how does it change if air friction is igno f -,san*ti: yurj;g+pfb8 -kored?

  As a freely falling object speeds up, what is happenibh9nb k6inlh7 *vf wl ky:o,x 2)de/,vng to its acceleration, how does it change if9hbvo vk*7wb, /2xdl6fkny i,h)en: l air friction CAN NOT be ignored?

  An object that is thrown vertically upward will return 30ma1z kf4ry1-++dr- ka rf* ;efvo6eh efogqto its original position with the same speed as it had initially if air resistance is negligible. If air resista1 qoffe34 f+g6z aermky-*r-dk0a1; fo+hvernce is appreciable, how will this result be altered?

  An object can have zero velocity l6,yta+ oww1j kh(pd)and nonzero acceleration at the same time.

  An object can have nonzero velocity and zero acceleration at the same t.cks:h)j; (glc f huu 0v+5)1utuyjwvime.

  An elevator moving from the second floor to bcsvys1 a72z bmz,e2) 5v672bm m xehv4(ebzbthe fifth floor making no stops along the way has zero accey4vsh 22 mbmbb bvv)b7e7 eazc5,m6x es21z(zleration all the time.

  A rolling ball moves9- u+izsjo jo+ from $x_1=1.9 \mathrm{~cm}$ to $x_2=-4.6 \mathrm{~cm}$ during the time from $t_1=2.2 \mathrm{~s}$ to $t_2=5.3 \mathrm{~s}$. 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 $x_1=2.5 \mathrm{~cm}$ and at $t_2=3.3 \mathrm{~s}$ is at $x_2=7.6 \mathrm{~cm}$. What is its average velocity?  (数值)  $cm/s$

  A person jogs eight loqr8r zw0b. i (vbwdp nwwp8:87qw9 )complete laps around a quarter-mile ($1 \; mile = 1609 \; m$) track in a total time of 7.5 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 115 w3x)il8 )buxw7 tzna :m away in 12.6z87l uit3n)ab: wwx x) 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 fromo kya3*8zt7/i cb1efy $11 \; m/s$ to $23 \; m/s$ in 5.0 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 fromhh;bd;beq0ch g9m -fy+i s 9+g $19 \; m/s$ to rest in a distance of 83 m. What was its acceleration, assumed constant?  (数值)  $m/s^2$

  A light plane must r2bn/tr yel52x(/cv gem4lyk -l8fx)peach a speed of $33 \; m/s$ for takeoff. How long a runway is needed if the (constant) acceleration is $2.4 \; m/s^2$ ?  (数值)  $m$

  A world-class sprinter can burst out of the . pc(1jp8l+d7vdeoz fblocks to essentially top speed aboutp7ol8dd vj+e1z.(f cp $10.6 \; m/s$ in the first 10.2 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 speed of4wyr/ kdm 0t/5tht3eda- oxb 8 $21 \; m/s$ to rest in 4.93 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. Assuming lbl 7m(b h)vk5a h l)vb(l5b7k mdeceleration of $7.00 \; m/s^2$, estimate the speed of the car just before braking.    $m/s$

  A car is behind a tr+ yfm5i poh-ufb 5//anuck 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).    $m$