Suppose that an object travels from one point in space to another. Make a comp n-c ebcye8s-4+xu.vtcm3id 6ari84enx c6t .bmdve cs3u -c-iy+son between the displacement and the distance traveled.

  When is the average velocity of an object equal to thu;m vmrnk4no 8d66 bx0tkc/z1e instantaneous velocity?

  A new car manufacturer advertise risgf51t/uii/l)i0me ( og0ws that their car can go "from zero to sixty in 8 s". This is a descrtifl1os g0iwre 5ii ug0 /m)(/iption of

  An object moving in the +x axis experiences an acceleratekzuzzxdn 33e8 )5y9iion of $2.0 \; m/s^2$. This means the object is

  Suppose that a car traveling to the East (+x direction) begins to slow downz2wrlfwn9d4n6ke 1lxa0/y9 e as it approaches a t wy / wenn61zl90lxfk d4are29raffic light. Make a statement concerning its acceleration.

  Suppose that a car traveling to the West (-x direction) begins to slow down ac.szt0kh+. gj s it approaches a traffic ligh.h+tgc zk j.0st. Make a statement concerning its acceleration.

  Suppose that an object is moving with a constant vel;bwtt cm wy50,ocity. Make a statement concerninwb0 my,t5;t wcg its acceleration.

  If the velocity of an object is zero, does it mean that t/u * 96 km:2bxftswzzsgg+4bb he acceleration is zero? Support your answer with a6bw z9g+*uxfb:4/smsb tk g2zn example.

  Can an object's velocity change direction when its0 t2 -k-)e kilptn7miig jt1.5yy eds) acceleration is constant? Support your ae2i0edty --ls ytgi5 m) kij1).p 7nktnswer with an example.

  Suppose that an object is moving with constant acceleration. Maxoj2c)4q b: tb8mw4ty gs1fc:ke a statement concerning its motion with4:g)cw4 o:tj bcb12s8fqyx m t respect to time.

  Can an object have increasing speed while its y)afj3 oh p m+k*c:yh7acceleration is decreasing? Support your answer with an exy )m3h fycj oha7k*p:+ample.

  Suppose a can, after an initial kick, moves up along a smooth hill of ice. Makuh ,wx r /h gh*tuuw 2/uclb1*s11tx6me a statement concerni c2 uh1u/srwxh,u *t x/h*lw1ubg6 mt1ng its acceleration.

  Under what condition is average velocity equal to the aveozy wp(p(c i)o suw o6ks+q525rage of the object's ino5oskzy2p( qic( u wops )w56+itial and final velocity?

  Objects A and B bothz;.a pd+afl csp fn0+ 5wc 0dv60.dgvzju)0wj start at rest. They both accelerate at the same rate. However, object A accelerates for twice the time as object B.fg0 zvd0wu.0 cdsjl 65 0) ;vnjdpw.fc+apz+a What is the final speed of object A compared to that of object B?

  Objects A and B both start from rest. They both acce7fm;7o i5km aflerate at the same rate. However, objectm i ;ofamf775k A accelerates 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 released from rest and fal +yw,0ht8g r1s6zlt1fl g8ekqls in the absence of friction, which of the following is true concerni 0krgl6+s,ghqw z18fyl1 8e ttng its motion?

  When an object is rels) zqr3 kx9f7xeased from rest and falls in the absence of friction, which of the following is tru3s9xzqrkf7) x e concerning its motion?

  Suppose a ball is thrown straight up. Make a statement about the velocity a4 x +t+2it*ne5icx4k 7 oxrtpcnd the acceleration when the ball reacheto+p24ni x7 cex t 54+kirx*tcs the highest point.

  Suppose a ball is thrown straight up. What is its acceleration just before it rr m+v63:d vznueaches itsd:6mvv 3+ zrnu highest point?

  Suppose a ball is thrown straight up, reach9i6 hz // hoa:ajskjizn5b68q es a maximum height, then falls to its initial height. Make a statement about the directi z sj/zb/aikj9q6n o 5:hiha86on 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 initi- 3; -bkqd/ehupb 4gzhaby33 ral height. Make a statement about the directiobk;ruy3 3q4 hz bh/-e3b-apdg n of the velocity and acceleration as the ball is coming down.

  Suppose a ball is thrown downward in the absence of air res,xl6pzxgim qc/ 79 djl6p7y cbfl9f2:istance. Make a statement concernincg9f7lf6,9c7 p/zdj6iy qllb2mx x:pg its acceleration.

  Suppose a skydiver jumps from a high-flyingtdflyv 7w7*(e 3ny4iu plane. What is her acceleration whe (v4ye l*tnuwy73 dfi7n she she reaches terminal velocity?

  A ball is thrown vertically upward with a speed v. An identiczaz7xkd u/ze.ym 4 rq41(xg8aal second ball is thrown upward with a speed 2v (tz8zqzdaku7ygem.14(r/ x4 a xwice as fast). What is 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 second later, ball B )xyipssoz:uok,.e)2 is dropped from the k) ioxuse)p,o:. 2 yzssame building. As time progresses, the distance between them

  Ball A is dropped from the top of a buildin.iy,cjku+8 kwwl+v9d o, w,t hg. One second later, ball B is dropped from the same building. As time progresses, the diffi.,u+cjdwkw w +o yl,89kvth,erence in their speeds

  Two objects are thrown from the z.zt9uj, a*:pdw j 0zftop of a tall building. One is thrown up, and the other is thrown down, both with the same initial speed. What are tz0:w . u, *ajzp9dzjftheir speeds when they hit the street?

  A brick is dropped from the top of a buildic4xu auq0)o uj-5ztxb lv-d*8 ng. A second brick is thrown straight down from the same building. They are released at the same time. Negl-o)0 ubzjqt8 4l-xucudx5 a*vect air resistance. Compare the accelerations of the two bricks.

  An object is moving with constant non-zero velocity in the +x axis. The positionia3 c9*a * niv41st:eum nds9m versus time u4t*i 3m a*v91d:einnssa9cmgraph of this object is

  An object is moving with copzzc8(r( 0.lsuj 9fhjnstant non-zero acceleration in the +x axis. The position versus timzhul8( 9 j.sjzf pr(0ce graph of this object is

  An object is moving with constant non-zero velocity in the +x atlupylel ;/ j5u)cc:6 s kt-b0xis. The velocity versus time graph of tlp / tyt5:j)ellu ks ;cucb-60his object is

  An object is moving with constant nnucy8 add21n 9bb ;2i;tmp+bwon-zero acceleration in the +x axis. The velocity versus time graph of mw1b2d2dbp +8nut9nc;y ;a ibthis object is

  The slope of a position vefra 88:7zx -9ag8 gjr:whntau rsus time graph gives

  The slope of a velocity veob av33e /a+ehrsus time graph gives

  The area under a curve in an acceleration versu3 uz3 *k4tjzrus time graph gives

  The area under a curve in a velocity versus time graph givesc/b oz9z79n6 kntfz*i hyz -5z

  If the position versus time graph of an object is a horizontal lie owm74fam.gl)sg1 z/ fpt;9mk.l +ebne, the object )l.9g;e7s +fb/ oe zkg mpfw14mt. mlais

  If the position versus time graph of an object is a vertical line,o::)*a 092fydqy rpz w1e gj xvi(w/pv the object is*qfjz)0y(:9y2w 1 /evo:p vadprwixg

  If the velocity versus time elca2 *xo+7u b e2ao9ggraph of an object is a horizontal line, the object is2x e*go9l7oea +a2 buc

  If the velocity versus time grdbtt7 us*o+w7aph of an object is a straight line making an angle of 30 degrees with the time ax7t stuwo bd*7+is, the object is

  An object moves 15.0 m north and then 11.0 m south. Find both the distance trm;;yd wu*sd3l4 ;s7rkfrme6 i avewu;ml m 6ier s37s dyk4*;fdr;led and the magnitude of the displacement vector.

  A boat can move at 30 km/h in still water. How lmddh0;,ge(a/pto xh (j56nh iong will it take to move 12 km upstream in a riveat 0g5e/mh;d( x o6n ihp,hjd(r flowing 6.0 km/h?

  55 mi/h is how many m/s? (1qrygux,-,kk: a/izv -/jv 8q z mi = 1609 m)

  What must be your average speed in order to tra zsn) cslx/zn2r -5cw0vel 350 km in 5.15 h?

  A runner ran the marathon (approximately 42.0 km) ix+jgwbwr mi++ba * (c1n 2 hours and 57 min. What is the average speed of the(* bwi1amg +r+x jwcb+ runner in m/s?

  A car travels 90 km/h. How long does it take fxyr:wfd a, +7for it to travel 400 km?

  A ly (light year) is the distance that light travels in ow9forau9 1: h3zt)zy rne year. The speed of lirua wh1):yt3z99rzof ght 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 look88e686m )gs,usge* tkq ibbtc to the side for 4.0 s, how far do you travel during this inattentive periode*)t 68sgkgei8c,mu8b6sq bt ?

  If you run a complete loop around an outdoor track (400 m), in 100 xwq2zr2)lk ig k3+e p7bc(h *bs, your average velqrp3k 2kc2li bbzh*)xe(wg7 +ocity is

  A polar bear starts at the North Po5 uk0* 4-hirkxqbc, ycle. It travels 1.0 km south, then 1.0 km east, then 1.0 km noi4bc 0xc-5* kkyuhr, qrth, then 1.0 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 1.0 km south, then 1.0 km m hn7m;3ab)e2qqg/e veast, then 1.0 km north, then 1.0 km west to return to its starting point. This trip takes 45nq) mvm;e bha/37q2eg min. What was the bear's average velocity?

  You are driving home on a weekend fbs7i mjd t(2egj,fy6h:4 (x5on2e fsorom 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 j:5d ( i6s meonj fb2hgoyx4 sf2(7e,tis your hometown from school?

  A motorist travels 160 km at 80 km/h and 160 km at 100 gxyn mk7s ():xkm/h. What is the average speed of the ykn 7():ms xxgmotorist for this trip?

  A motorist travels for 3.0 h at 80 km/h and 2.0 h at 100 km/h. What is h obot)4f(j0o ker average speed for theo(kb jtf)04o o trip?

  An airplane travels at 300 ms/b.7 2hytek ni/h south for 2.00 h and then at 250 mi/h north for 750 miles. What is the average speed f2 ks.n/b yet7hor the trip?

  In a 400-m relay race the anchorman (the person who runs the last 1fmg:k0ct81 pcq /,hiz00 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 starts the final leg of the race, in order thakphfc ,1 ig: qmct8/0zt the team A runner not lose the race?

  A car decelerates uniformly and comes to a stop after 9 s. The car's averab2kw lnm7ib(4rs;1ghge velocity during deceleration was 36 km/h. What was the car's deceleration mr(sb; k7w4g i hln1b2while slowing down?

  An airplane increases its speed from 100 m/s to 160 m/s, at the average rate wb bl4hp 9b1e5of bb1 hb p9w5el4$15 \; m/s^2$. How much time does it take for the complete increase in speed?

  A car traveling 60 km/h accelerates at thae 8 8y05pmbni i;*,8ndvo/jwyocr;c e 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 acceler7l 3cj/e w.rzedx,/emates 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 accedhdlm 0 igx/5v+d* 8e n1kuxzud le/:;leration of x /15dem/iu+dzvleg xud; h* 0:lk8d n$2.0 \; m/s^2$ for 15 s. At the end of this time, what is its velocity?

  A cart with an initial velocity of 5.4 m/s experiences a cot(51c h/rebt instant acceleration o( e1hi/r 5bttcf $4.5 \; m/s^2$. What is the cart's displacement during the first 8.3 s of its motion?

  A bullet moving horizontally to the ri gqj*y2 m zp9+l ;:hbvu+yj5l3pxq*e gght (+x direction) with a speed of 272 m/s strikes a sandbag and penetrates a9h leyz+*u*qj ppbl :5g xq +j2g;v3ym distance of 68.85 cm. What is the average acceleration, in $m/s^2$, of the bullet?

  A jet fighter plane is launched from a catapult on an ai,pu1 t,nbmw 0aq;9kzarcraft carrier. It reaches a spea9 b,qwamn1uzk;, p0ted of 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 accekt 6d+ u v6)v1jqjqz.w ezve ()lx7:grleration 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 dj1b+g0o yr3otgk ,85o ci2ai tistance of 200 m. What is its average acceleration?gogi+3,tr5 a j0okc82ti y1bo

  An object starts from rev bg ,: 8yf3z*pob5jlbg*dq 9qst and undergoes uniform acceleration. During the first second it travels 3.4 m. How far will fy5qdbq b:8g*, 9ljpvbg*o 3zit travel during the third second?

  An object is moving in a straight line with constant;(9zus3rzo r ot1+txj acceleration. Initially it is traveling at 16 m/s. Three seconds later it is travelingt (o1xjz;rru+39zs ot at 10 m/s. How far does it move during this time?

  A car starts from rest and a+/kv13pmta c zo1 8dfdd *l)ydlc0 b)nccelerates 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 tiresb1y36t c(vwh ncbos3mhb:, ,n on a 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 tur13l; p. zu8bd)ccvtqx ns green, a car that has been waiting at the intersection starts 3.vp cczu;dt1) 8xblqahead 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 speed of 12 m/s on the surface of p*1 evpt x g1hcr-c6c5dlanet X where the accelera 1vtcc6cx5p*-rhe g1dtion 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 surfacetxc7 gf5 bq+h +sr)0cr of planet X where gcc7fxq bt5 )hs +r0+rthe 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 surfaeow.no(r (3apfkuz o/ hls; qdc;).) cce of planet X where the acceleration due to graviz.lf(eo.r(;hpdwkc u)qon s /;c )3aoty 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 ks2s7 lr8n8qe9kijq wd775agwith a speed of 14 m/s on the surface of planet X where the accknq k a iw7ge2859sr qdls78j7eleration 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 gfm95,tbkl 9 ecreater than 0.10 s. If your friend holds a ruler between your fingers and releases it without warning, how far can you9f clm e5b9tk, expect the ruler to fall before you catch it?

  A ball is thrown upward at a velocity of 19d9la t t:hpn2/.6 m/s. What is its velocity after 3. l9t :h2pn/tda00 s?

  A bullet shot straight up returns to its startg1l ty1: o5o6 ybsl8d8d*ffcying point in 9 s. What is the initial spec:dfyo 1 l8g ft1dy6* 5lo8ybsed of the bullet?

  A ball is thrown straight up with a speed of 36.0 m/s. How long doe1/ayx7v hzv e snpid21ztg 1r919v*p qs it take to return to its starting pointpy2v*v17a1rqhe/xvzdn9 igst 1z9p 1?

  A ball is thrown downward from the top of a building h+i ,/hk7 h(cw:l6lq1 sydpfe with an initial speed of 30 m/s. It strshl(k6ic1wl ey p/dq,f7+ :hh ikes the ground after 1.7 s. How high is the building?

  A ball is thrown straight up with a speed o 3teg(knq.tx *o8x/ozf 30 m/s. (only fill in numerical value in to.k3x* (ze xgt t/oq8nhe 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 4+e,2kq v u5h+-*gzf4vz 7fvoen loez -9.5 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 8 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 8.0 m above the point of contact a second time.  (数值)  $s$

  In Fig. below, what is the velocity at vx +rl6:zbj6p u )6biot = 1.0 s?

  In Fig. below, what is thekr0 .e;9mt3;grhczv g( ua9 5l-jd ace velocity at t = 2.5 s?

  In Fig. below, what is the velocity at t = 4.0 s*n w3klg *6wa-n tyyv-?

  In Fig. below, what is the velocity at jx u:w-c0s z/xu2ocux:2 dcftdse637 t = 5.5 s?

  In Fig. below, what is the average velocity from 0 t)vqx49wvr.h tj: 5 r*eti v8izcrr69wo 4.0 s?

  In Fig. below, what is the average velocitmjs)9g0w lp3c; c 0 puh;kerexx9hr-1y from 0 to 6.0 s?

  In Fig. below, what is;2ppyprpb c9xn47oee l g7ss7:xwe/- the acceleration at 1.0 s?

  In Fig. below, what is the accel*pg/lvzpcbeha2 7y:*eration at 3.0 s?

  In Fig. below, what m 6n/cdr/,3erum;eoth0fo4yis the average acceleration from 0 to 5.0 s?

  In Fig. below, what is the average acceleration frymql3pj 3g/9nie *z:( sf;oxmom 0 to 8.0 s?

  In Fig. below, what is th u14py kfj0g0-kv uth5px,sr,e displacement from 0 to 8.0 s?

Does a car speedometer measure s m9byyjh b/k39. gz3uxpeed, velocity? {speed|velocity}

  An object can have a varying speeqyp:q e cy1 6p l:0yuy3e2ck.9o is;qcd if its velocity is constant.

  The velocity of an object caon 9fg2zl i ic;0 a)k;d0ikk6pn be negative when its acceleration is positive.

  If one object has a greater ilpz zpd, 4vlfxd.: )8x i+b*mspeed than a second object, the first must have a greater accelerad+lfx8di,bmixp4lz:z p. v* )tion.

  Two cars emerge side by side from a tunnel. Car A 8*63ck jrvbh ;l0idljis 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 2f89 mzwiozg -as its acceleration decreases.

  A baseball player hits a foul ball strw f9b ne4 8mp6q8we3noaight up into the air. It leaves the bat with a speed o3e8nno4qwb9p wmf 8e 6f $120 \; km/h$. 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 accelo6kqamdy;e)f r) i7 ) dd2f-fyeration, how does it change if air friction i7-) dffi)2dda6kq o;femr)yys ignored?

  As a freely falling object speeds up;zgw7zo i 7i6p, what is happening to its acceleration, how does it change if air friction p76zo;wgi i7z CAN NOT be ignored?

  An object that is thrown vertically up5zqj 1*2igxipgucr +5ward will return 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 be alx q crzp5*i21jug+gi5 tered?

  An object can have zero velocity and nonzero accel7s9 rooikc.rin(dq t79d u01xeration at the same time.

  An object can have nonzero velocityceg) py9kyz83 and zero acceleration at the same time.

  An elevator moving from the second floor to the fifth floor making no stops alvvyw n7..+ ek-r6,t:4k.xy vd4kz fon;p zj ohong the way has zero acceleration all kke.v vopyozfhk76t xy , n j.+;n-d.:44vrzwthe time.

  A rolling ball moves fromh;, vx xtm8u4d $x_1=2.5 \mathrm{~cm}$ to $x_2=-5.6 \mathrm{~cm}$ during the time from $t_1=1.3 \mathrm{~s}$ 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 $t_1=-3.1 \mathrm{~s}$ is at $x_1=3.3 \mathrm{~cm}$ and at $t_2=4.1 \mathrm{~s}$ is at $x_2=8.0 \mathrm{~cm}$. What is its average velocity?  (数值)  $cm/s$

  A person jogs eight complete laps alt/obmwt x nh 1+*-wt(round a quarter-mile ($1 \; mile = 1609 \; m$) track in a total time of 6.9 min. Calculate (a) the average speed  (数值)  $m/s$ and (b) the average velocity    $m/s$

  A horse canters away from itsc1+;gm yww-vnrk*4 cna aw*2p trainer in a straight line, moving 114 m away in 13.8 s. It then turns abruptly and gallops halfway 2+*;agy14w v ncw*mkw rnca-p back in 4.5 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 froupy;fi,6 9: cnsmv 2ixm $12 \; m/s$ 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 from 35jgy f vhfy2,6 *pczs 32pdrb$19 \; m/s$ to rest in a distance of 67 m. What was its acceleration, assumed constant?  (数值)  $m/s^2$

  A light plane must reach a speedxb6::k q+uotc of $33 \; m/s$ for takeoff. How long a runway is needed if the (constant) acceleration is $2.3 \; m/s^2$ ?  (数值)  $m$

  A world-class sprinter can burst out of the blocks to essentially toapv./x k y,,sgp speed about ,pa,. xy/kgs v$10.3 \; m/s$ in the first 13.7 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 from a s,ub,-f j yq0f.ntr/yrpeed of $21 \; m/s$ to rest in 5.35 s. How far did it travel in that time?  (数值)  $m$

  In coming to a stop, a car leaves skid mark9-)dkjc rr fl:kk -6r;ugpxy8 s 92 m long on the highway. Assuming -lr cyk; p rfk8x6r- )kdujg:9a deceleration of $7.00 \; m/s^2$, estimate the speed of the car just before braking.    $m/s$

  A car is behind a truck goi- y)kh0rvt9+jl aeo*gng $25 \; m/s$ 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).    $m$