Suppose that an object travels from one point 9 tkm xw u6ujj ew28q/amd3 b0/lce..qin space to another. Make a comparison betu90amxujlqckwmewd q 6b/ .t/23j 8.eween the displacement and the distance traveled.

  When is the average velocity of ahqsov /a (wz ,mno11g:eex87l n object equal to the instantaneous velocity?

  A new car manufacturer advertises that their 6pu5mjt 5iew1tm**decar can go "from zero to sixty in 8 s". This is a descriptio5 *5*1twu e6itej dmmpn of

  An object moving in the +x axis experiences a f6db1h rmk(hs)(x:cf-h i+f in acceleration of $2.0 \; m/s^2$. This means the object is

  Suppose that a car traveling t we v kdcg0h,a8f,fu28o the East (+x direction) begins to slow down as it ahvu8,2 fckwd e0gf8,a pproaches a traffic light. Make a statement concerning its acceleration.

  Suppose that a car traveling to the West (-x direction) begins to b s7;mhzynvgxkhbb6gj tk, ,1u((s-0slow down as it approaches a traffic light. Make a statemeg(gut-h0snjkz(,76 ,mvhsx; bybb k 1nt concerning its acceleration.

  Suppose that an object is moving with a constant velocity. Make a statmhns5ej,;hfmo( t4 6wement concerning ito(;n 4hmw65 ,hjefsm ts acceleration.

  If the velocity of an object is zero, q*n, j6bxcje9 does it mean that the acceleration is zero? Support yo e,j9xcb* qj6nur answer with an example.

  Can an object's velocity change direction when4d 6ck;cu v q t- fiad4+:uv:h)kb5bhk its acceleration is constant? Support yoh54vhk:4) ub cb:q dai- 6tcdf+ k;uvkur answer with an example.

  Suppose that an object is moving with constant acceleration. Make a statementa*t o -fdgn :k.vi-ahn2;- udv t--:2dd.nk f hagv;an-u*ov iconcerning its motion with respect to time.

  Can an object have increasing speed while its acceleration is decreaed jsv)j,30vm sing? Support your answer with an examplsvj me3v)0d,j e.

  Suppose a can, after an initial kick, moves up along a smooth hill of ice. Makcq . 6ks*l:cvze a statement concerning its acceleratio:v6.kl ccsqz *n.

  Under what condition is average velocity equal to th81gadpqxr r 61e average of the object's initial and final velocity?1xar81pg rd6q

  Objects A and B both sta (t;miu1wys6 jgb ) 9mwe0ul8irt at rest. They both accelerate at the same rate. However, object A accelerates for twice the time as object B. What is the final speed of objecsmw y 8ub10il6 ) mijw(u;9etgt A compared to that of object B?

  Objects A and B both start from rest. They both accelerate at the samef3ji.f+0y4at *p z rq;(madoi rate. However, object A accelerates for twice the time as object B. What is thm; iya.fofz03qja4td( + ri*pe distance traveled by object A compared to that of object B?

  When an object is released from rest and falls in the absence of friction, wq5v,msvwbez 6x/c - 2thich of the following is true concerning its moc6te5,w v mv-zsq2/ xbtion?

  When an object is released from rest and falls in the absence of frictiq hgjs*vs,gd;0mi.j *on, which of the following is true concerning its moijj,vs .g;g h*0d*qmstion?

  Suppose a ball is thrown straight up. Mkzqra 2eu+gb)*5 yt t-ake a statement about the velocity and the u5tae) tzgr-+q 2y*kbacceleration when the ball reaches the highest point.

  Suppose a ball is thrown straight up. What is its a1bv fwy. d*ip1cceleration just before it reaches its highes1f.bd*piw1 yv t point?

  Suppose a ball is thrown straight t hd za+gv9zkcf z(,60up, reaches a maximum height, then falls to its initial h6ghd z9 (z,+cfvak0tz eight. Make 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 height, then falls to i vgb+x lr7e,*hts initial height. Make a statement about the direction of the velocity and acceleration as the ball is coming +lhe*xrg,v7bdown.

  Suppose a ball is thrown downward in the absence of air resistance. Make a j +t5g yk0j;ujstatement concerning it0j+j;ugk j5yts acceleration.

  Suppose a skydiver jumpha z6d i;y3xb,s from a high-flying plane. What is her acceleration when she she reaches terminal velociy,z6db3x ai;h ty?

  A ball is thrown vertically upwarduv rwte-0t r52 with a speed v. An identical second ball is thrown upward with a speed 2v (twice as fast). What ir uer-v2 twt05s the ratio of 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 the top of a building. One se+u u3)lw v l o9bh75oxfjfai4 q:elm-7cond later, ball B is dropped from the same building. As time progresses, the if )l:mewoja+5l93 7 l7 xf4uhvqbu-odistance between them

  Ball A is dropped from the top of a building. One second laa- cko2 7b7 1hefdqt*cter, ball B is dropped from the sam*ho b1fa cec72tqk 7d-e building. As time progresses, the difference in their speeds

  Two objects are thrown from the top of a tall building. One it3vr eq k.w*b6-b9zh ms thrown up, and the other is thrown down, both with the same initial speed. Wha b-em9zhr.kb6tq3 w*vt are their speeds when they hit the street?

  A brick is dropped from the top of a buildin 3(vc0a9qbycj g. A second brick is thrown straight down from the same building. They are released(b q 0cvyjc39a at the same time. Neglect air resistance. Compare the accelerations of the two bricks.

  An object is moving wi s::t0 ahz(tstth constant non-zero velocity in the +x axis. The position versus time graph (ast:0zh:stt of this object is

  An object is moving with constant non-zero accele ovikb96mfe9fe nlhd909:)dpration in the +x axis. The position versus time graph of this ob99f0lmi6o )vn99h ekd :bde fpject is

  An object is moving with constant non-zero velocity in the +x ax(72iysg6 kkfl 2z :nqlis. The velocity versus time gn7:y l (fizsl6k2kq2graph of this object is

  An object is moving with constanc.pydv-6gn2xj3+ c;nl dt9xit non-zero acceleration in the +x axis. The velocity versus time graph of this objec-.x 9 cx dp;ndiy2j+tlg 6v3nct is

  The slope of a position versus time i)x*b 6l/se hmgraph gives

  The slope of a velocity versus time graph t. cs :ynjypz(30q s,fgives

  The area under a curve in an acc x8gztr e16-rx 76rtltycp4a:9irq,(h lpd )ueleration versus time graph gives

  The area under a curve in a velocity versus mf7y tn.3xidfq dv/ (5time graph gives

  If the position versus time graph of an object is a hujhcu-0m3 io 9orizontal line, the object isom cuj3u0 9h-i

  If the position versus time graph of an object is a verti:le4b qtj4 a5jcal line, the object isl:ej t44a5b qj

  If the velocity versus time graph of an object is a horizontal line, the objeq .la6k*jl c83s2kze .fb/ue cct is/fz.l38 .u *cek lkjeqa6 cs2b

  If the velocity versus time graph of an oby(txqv5 -wrw1ject is a straight line making an angle of 30 degrees with the time axis, the objecx(1v 5tqy-rw wt is

  An object moves 15.0 m north and then 11.0y ,8nuno;i- ig;4esbu m south. Find both the distance traveled and the magnitude of the displ;oge ,i b4unnis u;-y8acement vector.

  A boat can move at 30 km/h in still water. How long will it take to lqm7/sb,rh27y *rj bwo qpf8,move 12 km upstream in a river flowing 6.0 km/hwly7q8,mb*s27,rh/ boqfp r j?

  55 mi/h is how many m/s? (1 mid;ca,e7ms c *vm q.ky. = 1609 m)

  What must be your averise e3uh/1 u bz g4;o6h26lqvsage speed in order to travel 350 km in 5.15 h?

  A runner ran the marathon (approximately 42.0oy r0yi du:;*j km) in 2 hours and 57 min. What is the average speed of the runnro:y j0 ui*y;der in m/s?

  A car travels 90 km/h. How long does i yk+s (*x;qn f;xw04pltzw)dl t take for it to travel 400 km?

  A ly (light year) is the distance that light t0sx kft)7q so-ravels in one year. The speed of l7k0fo tss x-)qight 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 as t( dr5u7x *;p0qdji(oo /qeblong a straight road and you look to the side for 4.0 s, how far do you travel during this inat(07o(equi j t*q o/d;rbxsp5dtentive period?

  If you run a complete loop around aoa7r;i jc6sc9n outdoor track (400 m), in 100 s, your average velr;icjc a67os9 ocity is

  A polar bear starts at the North Pole. It truc9um- o 8xj:eavels 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 4 c:e-mu9j8uxo5 min. What was the bear's average speed?

  A polar bear starts at the North Pole. It travels 1.0 z: )rbm) 9 tod3h:bbrtkm south, then 1.0 km east, then 1.0 km north, then 1.0 km west to return to its starting b)dbzm9 3)tor:brth: point. This trip takes 45 min. What was the bear's average velocity?

  You are driving home on a weekend from school at 55 mi/h for 110 miles. -qh7q/sk (+ qj s5jret It then starts to snow and you slow+ rj-(jqk/s7qhqest 5 to 35 mi/h. You arrive home after driving 4 hours and 15 minutes. How far is your hometown from school?

  A motorist travels 160 km at 80 km/h and 160 km at 100 km/h. What is 0izgbl16z:+;p8jtp cgz 2yjs :hr(tvx)vc 1wthe average speed of the motorist for thisr+izz 8csjzvjg0:bytp(l tp) g:1hv x 612w;c trip?

  A motorist travels for f* :nz5t-axwu 3.0 h at 80 km/h and 2.0 h at 100 km/h. What is her average speed for the trf5*n- wu:az xtip?

  An airplane travels attx 0qf96deln ysrc (8q53x:pq svmr*4 300 mi/h south for 2.00 h and then at 250 mi/h north for 750 miles. What is the average speed for thefn4qqrx0 rd 6 3mv pex:8sqs(9*ytc 5l trip?

  In a 400-m relay race the anchorman (the person who runs the l9)bj vkpn *p6 zkt)lq*ast 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 nlt)pb6 z)jp9k *q* vkstarts 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 10 s. The car's averajmbhc3/vf;-m+z + 5emrtj+kr ge velocity during deceleration was 36 km/h. What was the car's deceleration while c3 jjz;hvk r+5- fr b/mtmem++slowing down?

  An airplane increases its speed from 100 m/s to 160 m/s, at the average ra/a*psh;xftog*tie;ayzwf ( 6 l-z5) bte of *x6bywaz*i /);ttg oh(fzf5 lase-; p$15 \; m/s^2$. How much time does it take for the complete increase in speed?

  A car traveling 60 km/h accelerates at the rvbi1o-n fu;-mate 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 acc5/ zeypjanx(, v j1ez ,/i-boselerates 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 t+m7 u5 ysn0d/mdpxi4when speeds up with a constant acceleration ofn ym/wd5sxdi 0um7 p+4 $2.0 \; m/s^2$ for 15 s. At the end of this time, what is its velocity?

  A cart with an initial velocity of 1.3 m/s experien+t i-z-xn) itktf3 ,xmces a constant acceleration ozkm3 -t,itt- xfnx)+ if $4.9 \; m/s^2$. What is the cart's displacement during the first 6.8 s of its motion?

  A bullet moving horizontally to the right (+x direction) with a st o.b36ojl 2qxpeed of 322 m/s strikes a sandbag and penetrates a distj3 t.o62bq oxlance of 89.06 cm. What is the average acceleration, in $m/s^2$, of the bullet?

  A jet fighter plane is launched from a catapult on an aircraft5;6xg q:aciup;v s:;kw+ohun carrier. It reaches a speed of 42 m/s at the end of the catapult, and this requires 2.0 s. Assuming the acceleration i+ o ;xcpgu5uvq:6san; wi:h;ks constant, what is the length of the catapult?

  A car starting from rest moves with constant acceleration of uezte(kad+( r3.(fwwy f44s(rg r5xj7shsw9 $2.0 \; m/s^2$ 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 itsmj5ouo6 2za i9lq+kw. average accelerat + 659 kwom.jluza2oiqion?

  An object starts from rest an+ fzf2v uokc9v n0a.4ad undergoes uniform acceleration. During the first second it travels 7.4 m. How far will it travel during the third s0n+f2 kvazu9o 4fac v.econd?

  An object is moving in a straight line with constant acceleration. Initial3 3rk n7cl*g 7pks9(qnj gsdb7ly it is traveling at 16 m/s. Three seconds later it is tras7lk n*7 ( jb33qrgcd9pg7kns veling at 10 m/s. How far does it move during this time?

  A car starts from rest and accelerates unifw z,xi*ujm hu6 *4z/qg(udy7pormly 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 dece5rwjml 5.(mr+(kkgi+b vfqp5lerate 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 z7 qn fjv-sbd0*-qvk:turns green, a car that has been waiting at the intersection startsq-s0b:vv dkj qzf7-*n 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 speeeaq.n ejp xkm4syk;d vn+/z o+q0++;nd of 12 m/s on the surface of planet X where the acceleration due to d+ n++;ejkyq4+pm .ozq/0;s nknxvaegravity 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 pf(y7dhy h8j/ m/s on the surface of planet X where f/h(7jd h yp8ythe 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 sux4tdhgq l-s -*g4g /ukfe*s;frface of planet X where the acceleration due to graxhgt4sqs* fkg-f e *4l;d /ug-vity 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 thzh /h-x0l+zcxe surface of planet X where the accele+0 zh /-zcxlxhration 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 -jq;rm08e*+ cel.ucdpiiv- dgreater than 0.10 s. If your friend holds a ruler between your fingers and releases it without warning, how far m q jp-0cdv +rcel*.eui d;-i8can you expect the ruler to fall before you catch it?

  A ball is thrown upward at a velocityhc o;au2zoii5ue; :1k of 19.6 m/s. What is its velocity after 3.0o;:u z25o1c eiahiku ;0 s?

  A bullet shot straight up returns to its starting point in 4 y:h7 l,6nd+e ) um.iuva:3xqnap sj )bs. What is the initial speed of the+d3uqs:b uj67a.pve h na:yn)) ,mixl bullet?

  A ball is thrown straightu3z1(cs tl5 ey up with a speed of 36.0 m/s. How long does it take to return tot c u35l1sezy( its starting point?

  A ball is thrown downward from the top of a building with an initial speed of 23 yfr9q8oo/px+ m/s. It strikes the ground afpyo qrf+89/o xter 2.8 s. How high is the building?

  A ball is thrown straighgft,p0n0(azvlg*8v e3 qb m eo- lg60it up with a speed of 30 m/s. (only fill in numerical value in th60t*v ,vonqegezl8( gima3p-bgf0l 0e 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 qq1ru81s ri+v +tb 9vq(p.dnyablv j 93+l;ydwith a speed of 26.1 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 2 seconds later.  (数值)  $m/s$
(e.) Determine the time at which the ball pass a point 6 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 6.0 m above the point of contact a second time.  (数值)  $s$

  In Fig. below, what is the velocity at b;sa9ggmu12a t = 1.0 s?

  In Fig. below, what is the v1 x8dv3fj ncnpv /kw,6l o7on0elocity at t = 2.5 s?

  In Fig. below, what is the velocity /lt qz.- r+float t = 4.0 s?

  In Fig. below, what is the velocity at t = 5.5 s*-xr.c gcv9wec5t mzy7 4 vkh3?

  In Fig. below, what is the average velocity fromiq66/ k rozxq-vq7h a. 0 to 4.0 s?

  In Fig. below, what is the averagy.tt9i s5jbw 8e velocity from 0 to 6.0 s?

  In Fig. below, what is then)1/ib ajwyj9 acceleration at 1.0 s?

  In Fig. below, what is the acceleration(w)c s56b nzuxv 9vhz0 at 3.0 s?

  In Fig. below, what is the average acceleration from7e rxt q/uwxj3+)b,oh -ba fu- 0 to 5.0 s?

  In Fig. below, what is the acyl0mq e4s56m)6oysn verage acceleration from 0 to 8.0 s?

  In Fig. below, what is the dii.0:jojpfk 7 -ng// o-vmezck splacement from 0 to 8.0 s?

Does a car speedometer measure sp9u(xk3/ yedk/pve nk4)yy -wo:8.fpns9 bejqeed, velocity? {speed|velocity}

  An object can have a varying speed if its bugg ae,fv51p*mfwxk6v :llv1 +tg*5velocity is constant.

  The velocity of an object can be negative when its acceleratiouwcq7.f5lbrq,m 8r e) n is positive.

  If one object has a greater speed than a second object, thz );k-ux msmp4e first must have a greater acceleratik-u s4mpm;)zxon.

  Two cars emerge side by side from a tunnel. Car A isuazxt2 k+z t3- 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 abofc uewz0lgw/ )+43icceleration decreases.

  A baseball player hits a foul ball straight up into the air. It leaves thd z(s+jrei5i/ e bat withj+5/srie(d iz 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 speeds up, what is happening to its a2qjbs5oy tfg0q- ;qmf .)ni (qcceleration, how does fojyq.in0;ms)(bqqq f- g2 5tit change if air friction is ignored?

  As a freely falling object speeds up, what is happening to its acceleratiop.qjy o )7;clq0p8,8xnit vi kn, how does it change if air iqtv8 7 op q;jxl ),.py8n0kcifriction CAN NOT be ignored?

  An object that is thrown vertically upward will ret(:4ey9-cz q;tg o wo;r0nw ubturn to its original position with the same speed as it had initially if air resistance is negligible. If air resistance is appreciable, how will this result b (zb0cwto tg-eu:n9o;wyr; q4e altered?

  An object can have zero velocitwv 9k jjig-,:ny and nonzero acceleration at the same time.

  An object can have nonzero velocity and zerm8 ti8j3ssu d7zwi.3 ko acceleration at the same time.

  An elevator moving from the second floor to the m wu b/k4qh0d/fifth floor making no stops along the way has zero acceleration all m h/dkqb4w0u/ the time.

  A rolling ball moves from z.uke3a,k:hd8:c,9eg rvv7qosn s + cbnwt*+$x_1=3.3 \mathrm{~cm}$ to $x_2=-5.2 \mathrm{~cm}$ during the time from $t_1=2.1 \mathrm{~s}$ to $t_2=5.7 \mathrm{~s}$. What is its average velocity?  (数值)  $cm/s$ (only fill in numerical value please)

  A particle at $t_1=-2.5 \mathrm{~s}$ is at $x_1=2.4 \mathrm{~cm}$ and at $t_2=3.5 \mathrm{~s}$ is at $x_2=7.6 \mathrm{~cm}$. What is its average velocity?  (数值)  $cm/s$

  A person jogs eight co if(11 w4mulh+v8gs)erxw f c)mplete laps around a quarter-mile ($1 \; mile = 1609 \; m$) track in a total time of 9.5 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 94 m ) 04e9b732to 0dazn.4fuiry ero r yoeaway in 11.5 s. It then turns abruptly and gallops halfway back in 4.8 s. 2e.0yzf4yaer routb3r in doe) 0479oCalculate (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 fromyws60u3wo5zqgr l3 *m $12 \; m/s$ to $23 \; m/s$ in 4.9 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 qaw2n; md45tq $19 \; m/s$ to rest in a distance of 76 m. What was its acceleration, assumed constant?  (数值)  $m/s^2$

  A light plane must reach a spehs9ffn u c;q32ed of $27 \; m/s$ 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 blocy 7(6a7re f8v7g1zcpm *czibhr/lymyozs848 ks to essentially top speed abouz1/g s7z*ver7 lmcbymi87a84ph y6yoc fz(r 8t $11.3 \; m/s$ in the first 10.7 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 g8qaarg,tu0 2 1xm+ehfrom a speed of $20 \; m/s$ to rest in 5.65 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/b a0)i4uywde t/,,los *; p1zei aoge a decelerab1iotueg */,liezd;o)y /w aae4p 0,stion of $7.00 \; m/s^2$, estimate the speed of the car just before braking.    $m/s$

  A car is behind a truck l /u.tf6*a zrbgoing $25 \; m/s$ 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).    $m$