Suppose that an object travels from one point in5i w+ ;e,v4bjj4x h+amc6 zykb space to another. Make a comparison betweevwmzy jibjb ,x+46h;+ckae 54 n the displacement and the distance traveled.

  When is the average velocity of an object equal to the instantaneous velocitnshg*c3qs9/fy , i9 dxy?

  A new car manufacturer advertises that their car can go "from zero k2xs 7whnn:5y ka;;nmc ;:yeoto sixty in 8 s". This is x5; yakho2 e;:mywnsn: ;kc7n a description of

  An object moving in the +x axis experience k bx1z (zj.(5aadfxptid17 6gs an acceleration of $2.0 \; m/s^2$. This means the object is

  Suppose that a car traves+fl6hr1a0k9oct 9w cling to the East (+x direction) begins to slow down as it approaches a traffic lc htfr6kw 0o19s+ cl9aight. Make a statement concerning its acceleration.

  Suppose that a car traveling to the West (-x direction) begins to eie344k8bv0;9 h 6k mggxzdhislow down as it approaches a traffic light. Make a statement concerning its accelerati3ihekb xm44g 0z; ivekd 68gh9on.

  Suppose that an object is moving with a constant velocitbv1k m. :svqy;3lkyivy0-a 3b k0 h(yoy. Make a statement concerning its acceler h0:y v( y.o qbv;ym1b0kil3svk-k3yaation.

  If the velocity of an object is zero, doeg/vma1th gj.7t.+b ttajqwfa1 5i 9x1 s it mean that the acceleration is zerov.h ta1a jab qt xi 1t/.5w1mg7j9+ftg? Support your answer with an example.

  Can an object's velocity change direcps:c1plho9 qs5k;pz:jbb: n 8tion when its acceleration is constant? Suppo9: 5nb;pj:: b qz8hkss1lcpport your answer with an example.

  Suppose that an object is moving with constqvfd t5vf0(vob: e/:j ant acceleration. Make a statement concerning its motion with respect to vdtf:v f5/be0v:jqo(time.

  Can an object have increasing speed w ikxo(54yh,dh hla6; ohile its acceleration is decreasing? Suppor h5ixh6 yhad(4oko;l,t your answer with an example.

  Suppose a can, after an initial kick, moves up along a smooth hill of ice.ha5 :; ,0tbq-akhfg dw Make a statement concerning its acceldfka hq5t:a; hb-wg ,0eration.

  Under what condition is average velo: c ktql;lx5-vcity equal to the average of the object's initial and final velocc:lx5v kt-;q lity?

  Objects A and B both start at rest. They both acc3 +qzz1ab5knp elerate at the same rate. However, objecq a5zz1pkn 3+bt 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 the si+is 7f822 9ap,upifcuc p r03h 0lsadame rate. However, object A c 2dupl 20rp9f8 ai i,30asphsfi+uc7accelerates 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 releapn tgpvxv653pzvw 6(0 sed from rest and falls in the absence of friction, whichv vz0 (vp 3n6t5ppwgx6 of the following is true concerning its motion?

  When an object is released from resx -gyvyj2, td/t and falls in the absence of friction, which of the following is true concerning ,v dgj ty2-/yxits motion?

  Suppose a ball is thrown straight up. Make a sgu2yv, z69sory 1/ hcmtatement about the velocity and the acceleratioy c6gho1usm 2,yzr/9vn when the ball reaches the highest point.

  Suppose a ball is thrown struovc ;wj lsvlk i-kf8s(r773+aight up. What is its acceleration just before it reaches vlfs(jkkiu3 +vw8 -;r o7 7sclits highest point?

  Suppose a ball is thrown straight up, reaches a maximumso7 4gwvj0iv6f;:b *zvg nxbhq/4* kr height, then falls to its initial height. Make a statement about the direction of the velocity and acceleration as the ball is oqxb h0 gfksw ;i vbvv:4/ n4*7gr6*jzgoing up.

  A ball is thrown straight up:sc o(d*2 khyb, reaches a maximum height, then falls to its initial height. Make a statement about the direction of the velocity ao: *d(sch2ybk nd acceleration as the ball is coming down.

  Suppose a ball is thrown downward in the absence of air rek u6*bqxlj 0e+sistance. Make a statement concerning its kj0lx6uq +*eb acceleration.

  Suppose a skydiver jumps fr v6 d .q:a;vfwnx)yg3vom a high-flying plane. What is her acceleration when she she reaches termina3gfvxwvda :y6;qv) .n l velocity?

  A ball is thrown vertically upward with a speed v. An identical shpp;l g4:8v +1v yz. n4utxtssecond 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 s 8v4;h:x4zp+n gv1tytls.pu many times higher does the second ball go than the first ball?)

  Ball A is dropped from the top of a bui6. k-rq+q yf3qibc*55fo 9mmx/bi gmglding. One second later, ball B is dropped from the same building. As time progresses, the distance between 3.k 5m+/6*qqrf 5y mg bc9-qxfmiobig them

  Ball A is dropped from the top of a building. One secox v;*b5b1vf srnd later, ball B is dropped from the same building. As time prog;b*v 1rfs b5vxresses, the difference in their speeds

  Two objects are thrown from the top of a tall buildin ds26lyjo c cs5gow;2k(5 s.qog. One is thrown up, and the other is thrown down, both with the same initial speed. What are their speeds when qldcsc5o yo6 ok (.ws2s2g;j5they hit the street?

  A brick is dropped from the qflc3 m(dz j)9.9 b -o3widniztop of a building. A second brick is thrown straight down from the same building.zj i-9lifo9z3n (wq) d3bmc .d They 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. The p pdhsw*7ec d 0jny1g+8osition versus time graphdpc1se 07dj8y+n wgh* of this object is

  An object is moving with constan07gp6icjs vk25 dp4 -yzoz*oyt non-zero acceleration in the +x axis. The position versus zp o ypd0cz s*6j2g 4kyo5-v7itime graph of this object is

  An object is moving with constant non-zero velocity in thela.c *+p7/dpioykka9 t3t5or +x axis. The velocity versus til5i.ky a +opp3/ art*c9o k7tdme graph of this object is

  An object is moving with constant non-zero zus ,lk 8me(8aacceleration in the +x axis. The veloc8u, (eksmaz l8ity versus time graph of this object is

  The slope of a position versus t+vtd34 z434kxhbol utime graph gives

  The slope of a velocity vers9j7h 1i; w+b.jg )aruoi5zt qeus time graph gives

  The area under a curve in an acceleration versk3h 5w 1io7nptus time graph gives

  The area under a cur;a e;80g: yrmkte 9rqld1-etrve in a velocity versus time graph gives

  If the position versusx5bhx 5dh, z(x+z)gqe time graph of an object is a horizontal line, the object i z)d(e gbhq,+hz5xxx5 s

  If the position versus time graph of an object is a vertical line, tn;wnjhw snc8f ;c wm;.+9 vp(vhe object is;wn+ vhc9nws.nw ;( fp8jv ;cm

  If the velocity versus time graph of an object is a horizontal line, the objegq (n-*exo5o hct ish gen- *x(5oqo

  If the velocity versus time graph of an object is a straight line making an an:.atd) g rqsk2j vy:9cgle of 30 degrees with the time axis, the o)q skcdy: v9gja.tr2 :bject is

  An object moves 15.0 m north and then 11.0 m south. Find both the dis 2 )d9e8j(v1vmtbukx3 ni(bpckwfo 1 ;tance traveled and the magnitude of the displacement vect;tvf)9 2n(ebwcbuko ( di8x1mjp kv31or.

  A boat can move at 30 km/h in still water. How l.r2qlgf* )vz4cz+8 cmm jj x5bong will it take to move 12 km upstream in a river flowing 6.0 c2.jrvc5gm x+*zmb4zq f )j8lkm/h?

  55 mi/h is how many m/s? ( +ahf97hg+,3il- qg7sopb,hzxh-zrz 1 mi = 1609 m)

  What must be your average speed in orde -;vd fen8g3c *6ctthwr to travel 350 km in 5.15 h?

  A runner ran the marathon (approximately 42.0 k;z(g1 (hwe zikm) in 2 hours and 57 min. What is the avera1 (izk zehw(g;ge speed of the runner in m/s?

  A car travels 90 km/h. How 7-dgv 4 ro.zdtlong does it take for it to travel 400 km?

  A ly (light year) is the distance that light travels in onep2 :*db1a/qba yn+ gjn year. The speed of li qn2 +1*abbag:/pnj dyght 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 yovyt su8o ;dy nx,abj)+kma:-)u look to the side for 4.0 ,nabx +s8y a )k)-vumjdoyt;: s, how far do you travel during this inattentive period?

  If you run a complete loop around an outdom 3y.a33 mof+ikwwx:oj5 xok) or track (400 m), in 100 s, your average )o y5omi fwa.xj:+ x33w3 okmkvelocity is

  A polar bear starts at the North Pk+ur ct j 5*r8n,+lydh37 npavole. 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.vdt+rc 7,nhklay3 pju*r5+ 8n What was the bear's average speed?

  A polar bear starts at the North Pole. It travels 1.0 km sou am2u1edd+ cd:(e v7ingj93 zdth, 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 bear'md7z1: cn9aj2gie v (edd+3uds average velocity?

  You are driving home omuj .*ca :xz,k himh,0n a weekend 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 kc j:0x,i .m*h z,haumis your hometown from school?

  A motorist travels 160 km at 80 km/h and 160 km at 100 km/h. lmz o 6wjjqa99gh(q61gkn4 h)prc*9f What is the average speed of the motorist for thik)lhfqjjr 9w 49h1 gg(zma6o*6c nq9ps trip?

  A motorist travels for 3.0 h at 80 km/h and 2.0 h at 100 km/h. What is her of8.sw jp6dqt +, ga 3e,vuc.aaverage speed for the od 3gsp.uf6aqwv, j.t8e ,ac+ trip?

  An airplane travels at 300 mi/h q9f-t+yv xj9g1+ msxd, u o6wusouth for 2.00 h and then at 250 mi/h north for 750 miles. W s gqmu++y9fjwt,u6 vx9o1-dxhat is the average speed for the trip?

  In a 400-m relay race the anchorman (the person who runs the last 100 m) for teacj(; blm2nh +jm 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 raccjjn(2 ; lbmh+e, in order that the team A runner not lose the race?

  A car decelerates uniformly and comes to a stop after 12 xc8b gnf,d)1js 9.t ok5 eodk6s. The car's average velocity during deceleration was 63 km/h. t.dnsx9b8keg ,16ok)5 fcdo j What was the car's deceleration while slowing down?

  An airplane increases its k 8uc9 m(6abj2od; hry9 4)oz5wqcccrspeed from 100 m/s to 160 m/s, at the average rate of r c(h9wy cu4o6) mjr;5z8ba qcco 2d9k$15 \; m/s^2$. How much time does it take for the complete increase in speed?

  A car traveling 60 km/h acceleo0h 219xgycu/umj v0yrates 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 accelera(i* 5 8rmvnim,nn(zxwtes 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 wb b+c6ca.;frwith a constant acceleration of+c; bf ab6.crw $2.0 \; m/s^2$ for 15 s. At the end of this time, what is its velocity?

  A cart with an initial velocity of 1.5 m/s experpj 3 iwj6eo 71e69fyubiences a constant acceleration of oj6ey9e3pjw fi 76bu1$4.9 \; m/s^2$. What is the cart's displacement during the first 7.9 s of its motion?

  A bullet moving horizontally to the right (+x direction) with a speed o(ft y-l:tww r.f 476 m/s strikes a sandbag and penetrates a dist(rl.t-wyw:tf ance of 68.16 cm. What is the average acceleration, in $m/s^2$, of the bullet?

  A jet fighter plane is launcx;swrt2+ afc w(wf9 (vajpf z75a a)/phed 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 lengtf c 5 ;+pww/z9j av7ra(f2at w(asp)fxh of the catapult?

  A car starting from rest moves wi z37f v71-4dqv ln)fajpnrfa*i(mx o*th 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 in a distance of 200 m.;1k bzbe pr-ml.m/ wy;;qbi 5a What is its average acceleration;1ma rzb/p;em iq5bb;-y k w.l?

  An object starts from rest and undergoes uniform acceleration. During the fj j,w-, rw0ynyirst second y0, ,jrj nwyw-it travels 6.5 m. How far will it travel during the third second?

  An object is moving in a ij - fnairxs(dc7bqecu q.b35 9 +rn5+straight line with constant acceleration. Initially it is traveling at 16 m/s. Three seconds later it is traveling at 10 m/s. How far does it move during this es.ri nx5q5 df ic739jcqu-b+nb+a(rtime?

  A car starts from rest and accelerates unijncjm pj ;q3jh2,b y*e+uo. 7eformly 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 cw0zhnps u8*9a dry road 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 5q6swlop k9p-plt18 d turns green, a car that has been waiting at the intersection starts ahead wi-5o61p wpl8sd9 pkltqth 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 speed of 12 m/s9i)r88cc q5mopetd 1s on the surface of planet X where the acci89 p 1)qm85orsctcedeleration 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 the surface of p-y9y u,b lk(z::b1pn w*frlavlanet X whellp (,f:vbwy:b k z1nrya-u 9*re 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 surzq 7w(1xl at9yface of planet X where the accellw(x9 z 1qyat7eration 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 of 14 m/s on the surfacp+zxc-d. t g6pp*m ik)e of planet X where the acckip6.*cxzm td) p p+g-eleration 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 0.10 s. If your fvzf,t5 kf ; 4n-qd *9e+erdzviriend holds a ruler between your fingers and releases it without warning, how far can you expect the ruler to fall before you cviv 9eqzddf4kz- +e t;n*r,5fatch it?

  A ball is thrown upward at a veloilc+, herg.0 dcity of 19.6 m/s. What is its velocity after 3 +,.lhi c0edgr.00 s?

  A bullet shot straight up returns mp0u)2dj (caoto its starting point in 14 s. What is the initiaauj dc )m02p(ol speed of the bullet?

  A ball is thrown straight up with a spe/or-w )usrk:i )x n krto5-r/aed of 36.0 m/s. How long does it take to return to its stnrrr/k)t 5 /swouo)xr:i -k a-arting point?

  A ball is thrown downward from the top of a building with an initial speed of 8 f) )ymykd 0.pzm/s. It strikes the ground after 6.7 s. How high is the buildiypz)f y)dm0 k.ng?

  A ball is thrown straight up with a speed of 30 0k9:gc(c jv vjfkac3y 19 n5szm/s. (only fill in numerical value cyj(j5vvkk39fs gn1c:a z0c 9in 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 speed of 31)aoetu2, mq :5 ph*dfg.5 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 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 velocitq+sty;49p8 )yx ;7snl ap5blu2crpuy y at t = 1.0 s?

  In Fig. below, what is the velocity at1fp 0z5xhoyt/m+u(xe t = 2.5 s?

  In Fig. below, what is t7 ,c-p -sx /daf:u wrntbe*k;ahe velocity at t = 4.0 s?

  In Fig. below, what is the ve7*mw*kg: kx / 9qsshyelocity at t = 5.5 s?

  In Fig. below, what is the average velocity frn2idsh m/0) kooe)2ieom 0 to 4.0 s?

  In Fig. below, what is the average velocity from 0 td1lucrcwa(e)g/yeuw;ni6w ,i3v k z /o)67dco 6.0 s?

  In Fig. below, what is the acceleration ay*em40-mzmvv r r8 3tot 1.0 s?

  In Fig. below, what is the aydb*/ wh ;4j3 3x uza-k1jhy)ml(qigb cceleration at 3.0 s?

  In Fig. below, what is t0 c:5fwurxy+ nl.2 ugzka s2yyb+0-wrhe average acceleration from 0 to 5.0 s?

  In Fig. below, what is xrf fqlf u,a cut-94zs10 nn:7pctt7)the average acceleration from 0 to 8.0 s?

  In Fig. below, what is the disc jp3xy u .+/vj;8waosplacement from 0 to 8.0 s?

Does a car speedometer measure speed, velocity? {speegitjp/lv: rb 9yuc8vs8o;ht 7(1yz,z d|velocity}

  An object can have a varying speed if its v;k4p6 ;lhz sokelocity is constant.

  The velocity of an object can be negative when its acceleration 5ksxz i kbidbigd(p ;u36;+q2 is positive.

  If one object has a greater speed than a d;cehx(w-0a ls gl2l t8g2d6qr l; *dq6mz .lfsecond object, the first must have a grll t 6sc .(6zmr*; 2gqq0-g fdh da8xdlw2le;leater acceleration.

  Two cars emerge side by side from a tunnel. Car A is traveling with iywqo o:s53 4uqx j)7ga 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 decrev+msfrq (y z:1ases.

  A baseball player hits a foul ball straight up into the air. It:iv-zg6xg qg f5 la*.d leaves the bat with a speedl q:g adgvg-i5z.x*f 6 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, what is happening to its accelerato2jdj3 ce+b+kion, how does it change if air friction is i3 jck+oe2j+bdgnored?

  As a freely falling obj6;f(;ydw2rdt tz a.(d- bmjly ect speeds up, what is happening to its acceleration, how does it change id; dwzfbmty(alr;(6d t .y2- jf air friction CAN NOT be ignored?

  An object that is thrown vertically upward will return t k,f7xsj)fmx *. yl;bjo its original position with the same speed as it had initially if air resistance is negligible. If air resistance is appreci.l)*;bjj7msf xf xy ,kable, how will this result be altered?

  An object can have zero veu 0y8 gmlme,l)locity and nonzero acceleration at the same time.

  An object can have nonzero velocity and zero acceleration at thed* 2zbyce- *lv same time.

  An elevator moving from the second floor to the fifth floor making no stops alon*gug+;ptc.9tmr 0 vsr(p b8it g the v t(9r* 0.gb+rpu8pmt; cgstiway has zero acceleration all the time.

  A rolling ball moves fly2x+qfi;ezgw );k 3grom $x_1=2.2 \mathrm{~cm}$ to $x_2=-5.0 \mathrm{~cm}$ during the time from $t_1=1.3 \mathrm{~s}$ to $t_2=5.6 \mathrm{~s}$. What is its average velocity?  (数值)  $cm/s$ (only fill in numerical value please)

  A particle at $t_1=-3.3 \mathrm{~s}$ is at $x_1=3.1 \mathrm{~cm}$ and at $t_2=3.1 \mathrm{~s}$ is at $x_2=8.5 \mathrm{~cm}$. What is its average velocity?  (数值)  $cm/s$

  A person jogs eight comple4eo(n(s7l.rj im s1 e6ctms5wte laps around a quarter-mile ($1 \; mile = 1609 \; m$) track in a total time of 6.8 min. Calculate (a) the average speed  (数值)  $m/s$ and (b) the average velocity    $m/s$

  A horse canters away from its trainern( wq) w(km:cj in a straight line, moving 93 m away in 10.1 s. It then turns abruptly and gallops ha) (ck(w nqm:jwlfway back in 4.7 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 frowij* x botm*. s-z/s6sm $12 \; m/s$ to $23 \; m/s$ in 5.5 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 fromgb/8 zmq i8ce3ylr)k k4br.gz5.ae3 f rce3:u $21 \; m/s$ to rest in a distance of 58 m. What was its acceleration, assumed constant?  (数值)  $m/s^2$

  A light plane must reach ap/8dky4dk vi. po5gk of7;s xqfp:w;1 speed of $28 \; m/s$ for takeoff. How long a runway is needed if the (constant) acceleration is $2.9 \; m/s^2$ ?  (数值)  $m$

  A world-class sprinter can burst out of the blocks to essentially top sqapl/a)/0bo w peed abou /w) paqlab/o0t $10.6 \; m/s$ 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 frd5ac8rb*ukgniv wh ow7-a.(2 om a speed of $21 \; m/s$ to rest in 4.83 s. How far did it travel in that time?  (数值)  $m$

  In coming to a stop, a car leaves skid marks 9f4ti51u2b- bu /apyfk 2 m long on the highway. Assuming a decel/tak p-iub 152f4yub feration of $7.00 \; m/s^2$, estimate the speed of the car just before braking.    $m/s$

  A car is behind a tru /l0 zoc:f+5 wshjc8efck 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).    $m$