Suppose that an object travels from one point in space to another. Make a5a:csx/i2kozn t,: lp comparison between the displacement and the distance tnilpc5:a /2,xk tz:soraveled.

  When is the average v7pw3+ e 0: v:bh2itb6hzq07doab mzimelocity of an object equal to the instantaneous velocity?

  A new car manufacturer advertises that their car can go "from zero to sixtb -vud/uwc3 (ens/bl)y in 8 dvs(/enlbc uw /u- 3)bs". This is a description of

  An object moving in the +x axis experiences an accelera qujf(lh;xi4,7gv.r3 jvr8c0, ift ndtion of $2.0 \; m/s^2$. This means the object is

  Suppose that a car traveling to the Easj65;kv/ z+j 8 xrxxcict (+x direction) begins to slow down as it approaches a c i5j/k z8j6x vxx+;crtraffic light. Make a statement concerning its acceleration.

  Suppose that a car traveling to the West (-x direction) begins6zfre 0iig0 j: to slow down as it approaches a traffic light. Maki ei60f:gzr0 je a statement concerning its acceleration.

  Suppose that an object is moving with a constant velocity. Make v/fs.h34(.vq2 w gzsqk(tzr za statement conv.th4zszvw .g 3skf zq2/( q(rcerning its acceleration.

  If the velocity of an object is zero, does it mean that3a oq50rhpq-y0.mjw l the acceleration is zero? Support your ansjla00q rpomw. qhy -35wer with an example.

  Can an object's velocity change direction when its accelerdnoj +uvr6-2u wem/(c ation is constant? Support you6c/er o-nwm 2juv+u( dr answer with an example.

  Suppose that an object is moving with constant acceleration. Make*c/p j4p*l p2b ) ad1;muwzzvf a statement co/)jvz;w2 *f cpp bdp*mul4az1 ncerning its motion with respect to time.

  Can an object have increasing speed 6x3wdvw.uad jgp 26-jwhile its acceleration is decreasing? Support youra6p6d23 gwuvjwdxj .- answer with an example.

  Suppose a can, after an initial kick, moves up along a smooth hill of ice. Makji n6+,ve w,kbe a statement con6k+jw ,,v einbcerning its acceleration.

  Under what condition is average velocity equal to the average6ax r q/dc*1sw of the object's initial and frswaxq*1dc6 / inal velocity?

  Objects A and B both s76j )h(of cbyfr9fnj0tart 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 object bncf)r(h ff6oj 079y jA compared to that of object B?

  Objects A and B both start from rest. They both accelerate at the same rate. 7mzle ss0p6-xi9qony8/ kod e 8wg6e+However, object A accelerates for twice the time as object B. What is the distance travelew/xze 6sso - nq9ylie7+8 0okd6mgpe8d by object A compared to that of object B?

  When an object is released from rest and falls in the abz 948udeolw+sf* 4csp sence of friction, which of the following is true concerning zwe4cs uf *s 98+old4pits motion?

  When an object is released from rest and falls in the 59j, faq x;xywk 8:cdqabsence of friction, which of the fo;,j a: 9k5y q8qcfxwxdllowing is true concerning its motion?

  Suppose a ball is thrown straight up. Make a statement about the velocn8:- lf)+eg y lic:cuwity and the acceleraf+-ynge8lwc:l) c:uition when the ball reaches the highest point.

  Suppose a ball is throi ypsq1bie15g 9i+ dl(wn straight up. What is its acceleration just before it reach(qiyi1 19bgi edsl5+pes its highest point?

  Suppose a ball is thrownm3v9mds,rn9 v straight up, reaches a maximum height, then falls to itsv9r3 9,dm nmvs initial height. Make a statement about the direction of the velocity and acceleration as the ball is going up.

  A ball is thrown straiknp5:a ;8qh bqr8;a cught up, reaches a maximum height, then falls to its initial height. Make a statement about the direction of thek cq8:u;ap8b n qh;ar5 velocity and acceleration as the ball is coming down.

  Suppose a ball is thrown downward in the absencetdv1 lmge fa7lt((-w ) of air resistance. Make a statement concerning its t(lfwlm1- ( )adg vte7acceleration.

  Suppose a skydiver jumpsb + lxxn0mdk3 u mrou0,v/.8nx from a high-flying plane. What is her acceleration when she she reaches ter/vmxu.u rxlbn0 k8dx 0,3n+omminal velocity?

  A ball is thrown verticalabi bp- t6u3v*2 dq,psly upward with a speed v. An identical second ball is thrown upward with a speed 2v (twice as fau,q sb-2 ad3p6pbt iv*st). 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. Onemu7xe1yq 5/ nl second later, ball B is dropped fromlqnymx1 75 e/u the same building. As time progresses, the distance between them

  Ball A is dropped from+g84 vohsivvx1vt+af5pe (m ; the top of a building. One second later, ball B is dropped from the same ma;+ 5sv4f vv18gopxthv(e+ibuilding. As time progresses, the difference in their speeds

  Two objects are thrown fl0cnqm300ekn q+mi ; brom the top of a tall building. One is thrown up, and the other is thrown do 0m;n3nl00kqi+m eqcbwn, both with the same initial speed. What are their speeds when they hit the street?

  A brick is dropped from the top of a building. A secongu +l1 1ee5lyo iai -zu8zy0yhi3g4q5 v eez:2d brick is thrown straight down from the same building. Thze3zo:4 e 1uqeue-i5gvi1a0y8z y hlyl52 g +iey 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 t8xd.rwf q1 8+sglg7p6hk ov;zcad ;x +he +x axis. The position versus time graph of this obs+.fd 8l8;1xqgo+ pw76g ;xzrhd kvacject is

  An object is moving with constant non-zero acceleration ie x4w78ogu s2zn the +x axis. The position versus time graph of this object is4 g2xuwzo 8e7s

  An object is moving with constant non-zero velo4j/p*m,w asus q e cjgmw( ;4xc-kk87gcity in the +x axis. The velocity vec gawkmmu 8qc-s*ek7xg4(, 4w/j ;p jsrsus time graph of this object is

  An object is moving with constant non-zero at2:5fc2nzjat :bt 3f ccceleration in the +x axis. The velocity versus time grt2tbnz:2: c5ft3af cjaph of this object is

  The slope of a positit(sh1m*4ieiu, 7q ;hacyl) nion versus time graph gives

  The slope of a velocity versus time graph gi ub +s(u :9z+gru 6nqwod*lr.ives

  The area under a curve in an acceleration vjrl,ifktzh( w+6- k 2nersus time graph gives

  The area under a curve in a velocity versus time gjv:3oj5fn2rsb69tm wa- vbw *raph gives

  If the position versus time graph of an object is a,r v3r;/iu6qkr,nrga horizontal line, the object isq ia,rrv r/3n;g,u r6k

  If the position versu,z ye 8j ra+ socf44;mnph)wpi5gh)6ns time graph of an object is a vertical line, the object is6 gnprfmhp)8ewn y5zj ;4s cio+)h4a ,

  If the velocity versus time graph of an object is a hogv lx,9 fcpgk)+j3 pw/rizontal line, the object isjw9/)v+xkgl3 gpp cf,

  If the velocity versus time graph of 0/b /pjyp ej0v+ uul0van object is a straight line making an angle of 30 degrees with theey lv0 0pjp +/j/vu0ub time axis, the object is

  An object moves 15.0 m north andv) *w0yu(en-2tf m+re zy acmgoo145x then 11.0 m south. Find both the distance traveled and the magnitude of the displacement vector0om x fzrw* -+ee(vm4ynu2tyc1g5 )oa.

  A boat can move at 30 km/h in still water. How long w2xxuh3)t)xec:w+ csput3p g5 ill it take to move 12 km upstream it xx)scu2)h5 tg+w ce 3u3x:ppn a river flowing 6.0 km/h?

  55 mi/h is how many m/s? (1 mi = 13rj06 u7txfu u609 m)

  What must be your aver)e,0my2r6 c0s 4gr5js o.3ofldqzueyage speed in order to travel 350 km in 5.15 h?

  A runner ran the marathon (approximately 42.0 km) in 2 *ion5lcd:dxfa2zih s0d(q5(hours and 57 min. What is the average speed of t55s:qdcznixa i( 0hod( d lf*2he runner in m/s?

  A car travels 90 km/h. How long does it take for r-i gkdil); q(kndvg g4l(-o.r-gpi7 it to travel 400 km?

  A ly (light year) is the distance that light travels in rh c*t89c,pswp 4f,gvone year. The speed of light is cwpfstr9pv48,g,h *c $3.00 \times 10^8 \; m/s$. 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 strl.1c4g.hwe pp zu/ 1gnaight road and you look to the side for 4.0 s, how far do you traveln/h 4w1pgg.z1el.upc during this inattentive period?

  If you run a complete loop around an outdoor track (400 m), in 100 s, you +o1plsae: (rjzhxz;k7uj g 50a()pl4 wwiz f8r avera :4 8g)p5(zezw+juzj o (a hlks ;xi7fpr0l1awge velocity is

  A polar bear starts at the North Pole. It travels 1.0 km south, t4gtq 7 )sg4qc g1;4t jxutr)wi,hxio1hen 1.0 km east, txq1o) wt 4 q,ruxisc)ttgg;gi14j h47hen 1.0 km north, 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 a0ok9w4gkq( 8a)o,cviga* r rtt the North Pole. 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 stak(wor0t, agvgi)ocq84*9k rarting point. This trip takes 45 min. What was the bear's average velocity?

  You are driving home on a weekend from school at 55c o ph24vuz9-v mi/h for 110 miles. It then starts to snow and you slow tocuvo-24 zhp 9v 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 d3 b+mqc00towm9tidjv8v4: 60z eesc 100 km/h. What is the average speed of the motorisvcd40 t0cvs390e:mjitq 8db +omw6e zt for this trip?

  A motorist travels for 3.0 h at 80 km/h and 2.0 h at 100 km/s nj9z1yz1ugo x6.-qyh. What is her average speed fo1s.x9y zg6n zo1y- ujqr the trip?

  An airplane travels at 300 mi/h8(qlfcu c tm2: south for 2.00 h and then at 250 mi/h north for 750 (2clqf 8 mtuc:miles. What is the average speed for the trip?

  In a 400-m relay race the anchorman (the person who runs the last 100e4:cpjf jyod fdkm(1n 7/0q-e 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 raqf/0- jed: 7o(ndfpje myc14kce, in order that the team A runner not lose the race?

  A car decelerates uniformly and comes to a stop after 9 s. The car's averaxsgrxx.* xo/ q4e3lxphl82o . ge velxxr 2/.gx*sox p3.x4lloqhe 8ocity during deceleration was 40 km/h. What was the car's deceleration while slowing down?

  An airplane increases its speed from 100 m/s to 160 m/s, at the a(l ttffzi72 mytk v3zn242w i6verage rate of 3k ywvl(t4i zmz7t fnif t2262$15 \; m/s^2$. How much time does it take for the complete increase in speed?

  A car traveling 60 km/h accelerannaok-j02 +iktes 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 tze;k 0bru* g+fym70 band 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 10ak4hx+q3ljh ow t x((-hvv v95dwd.r6 s. It then speeds up with a constant acceleration of ( 53dvxdh.kl ahw q(6rxwv4tv-9 oj+h$2.0 \; m/s^2$ for 15 s. At the end of this time, what is its velocity?

  A cart with an initial velocity of 4.6 m/s experiences a constant accelerapqervvgt, g5kj869qvpg*) y :tion of kr8ep g j,yqvv:vp) 5* q9t6gg$3.4 \; m/s^2$. What is the cart's displacement during the first 9.5 s of its motion?

  A bullet moving horizontally ixzlpf17 ,ta1 to the right (+x direction) with a speed of 315 m/s strikes a sandbag and 7lz xi1fatp1,penetrates a distance of 52.10 cm. What is the average acceleration, in $m/s^2$, of the bullet?

  A jet fighter plane is llt /sw whdc2n:80wa1z aunched from a catapult on an aircraft carrier. It reaches a speed of 42 m/s at the end of the catapult, and this requicwn 2:1 alsw/8 w0tdhzres 2.0 s. Assuming the acceleration is constant, what is the length of the catapult?

  A car starting from rest moves with constant acceleraqlx(( m(,h4y f a6f7gq7cunhjtion 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 itscnm, * rs4j/mmu j+:npi9 .edegobw 6bjd)f 1/ average acceler6 )p*rj :jmbnjmdg/9m+/becndu oi.w e4s1, fation?

  An object starts from rest and undergoes uniform accelert/ 0c l/oa(uaei k*da:q,sat,ation. During the first second it travels 7.2 m. How far will it travel during the third secondast* tqo ik ed(/0:a,a,l/ uca?

  An object is moving in a straight lv62e7 q ejb;coine with constant acceleration. Initially it is traveling at 16 m/s. Three seconds later it is traveling a c2vo6q;b 7jeet 10 m/s. How far does it move during this time?

  A car starts from rest cr wac2h qp/f95v9hhzaudyhy;ap78 9 ;h8 0 guand accelerates 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 decelerate at a5: o4xrb;aa yebout $5.0 \; m/s^2$ 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 jqfxl uet8h5-ixc*u33 r md8- the intersectio uej-3tr83qu8fdcxhx-l mi *5n starts 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 upwar 7w/-esudznl3 d with a speed of 12 m/s on the surface of planet X where the acceleration due to gr7 un3z-lsw/e davity 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 ye q( 6r xlm)ctku;33mzv+li+6shx-c the surface of planet X where the acceleration due toy+x3;r+3kcsu c66(hmxl lv )m -teizq 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 ofo* h1va0 fu(psui1 5;z7 zzogm planet X where the acceleration due to gravity is 5 ghvmzo z1zsfo7 ;a*0u1i(pu$2.5 \; m/s^2$. How long does it take for the object to return to where it is thrown?

  An object is thrown upward with a speed of 1 ;ke,io6. xjo)ha);l ycp: alz4 m/s on the surface of planet X where tha.6l;i;:,y exh c o)zkl)jo pae acceleration 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 th5)0t+iputv kcb qf)h*s h .b+can 0.10 s. If your friend holds a ruler between your fingers and releases it without warning, how far can you expect the ruler to fall before you catk5.ct)ts0cp+i+b )f qhbvu *hch it?

  A ball is thrown upward at a velocity of 19.6 m/s. What is it w ca8efsmiuo675k0l 5s velocity after 3.eu7a 5ks c65oimw0f8l00 s?

  A bullet shot straight up returns to its starting point in 6 s. What is the u g 3u5xr*t:yb8fk7pr,velp 4 initial speed o 5 8:3r*lrfye7 put u,gp4kvbxf the bullet?

  A ball is thrown straight upd b1h grnv*mls:n8c3bhc0xtkw;o3u)4z5k3 c with a speed of 36.0 m/s. How long does it take to retd3nmgccu)hts50;:k8*o3bn lr1x vc hw3b 4 zkurn to its starting point?

  A ball is thrown downward from the top of a building with an initial speed3*uc,puqblndhz3o/l : b ( 4lwm:zk2g of 11 m/s. It strikes the grc3p*zubo gmlud:/(n ,lqkhw 3zb:l42 ound after 4.7 s. How high is the building?

  A ball is thrown straight up w4 of;0e si+n 543ce( dczfbcekith a speed of 30 m/s. (only fill in numerical value in the blanks c4 s;dco(ne4k3eiff5b0zce+ )
(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 * -*tl(4vkaqdgh-ayvk6tff ) the air with a speed of 41.9 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 13 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 13.0 m above the point of contact a second time.  (数值)  $s$

  In Fig. below, what is the3w5 exrc4y zj, velocity at t = 1.0 s?

  In Fig. below, what is the z 5*sms;a4xfr velocity at t = 2.5 s?

  In Fig. below, what w4y n:gts(,6pmx qkzi2e .gj0is the velocity at t = 4.0 s?

  In Fig. below, what is the velocity at t x) wx p9f)l9j4doib8a = 5.5 s?

  In Fig. below, what is the average velocitym e ffbz-))ui8 from 0 to 4.0 s?

  In Fig. below, what is thj.+syrz6os 2 x aih5/apxig/, e average velocity from 0 to 6.0 s?

  In Fig. below, what is the accelerac7ons zi2loqymu3;k*t -( c+v tion at 1.0 s?

  In Fig. below, what is the acceleratio5(j,v bdzz**/jo xgtln at 3.0 s?

  In Fig. below, what is the a(c/ h9 r0o pmc :knfvet,8qu5uverage acceleration from 0 to 5.0 s?

  In Fig. below, what is the average acceleration from 0 to 3t.kd dd6 f1tx8.0 s?

  In Fig. below, what isn1kywu - 8e1qf the displacement from 0 to 8.0 s?

Does a car speedometer measure speed, velocity? {smpwzi3 haz,9w3f4qs 6peed|velocity}

  An object can have a varying speed if it8j8.r5vytm tf s velocity is constant.

  The velocity of an object can be negjwv pfc,* /a )/wa:w2v)yctoi fty:*zative when its acceleration is positive.

  If one object has a greater speed . glwz+ddjv45than a second object, the first must have a greater acceleratij .+wdzl45gvd on.

  Two cars emerge side by side from a tunnel. Car A is traveling with u4qufxt 6*l7*nt 0ywliqq. +wa 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 decr8k-xl1sg6.m o ec +mdheases.

  A baseball player hits a fonuu a)lo3.si8-lu fcnpa),8qul ball straight up into the air. It leaves the bat with a speed of 8ca n8-lq ns3 )louufipu ,.a)$120 \; km/h$. 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 accel 75t9e:h +9rs,yrkhtey e zw+0gz6fx deration, how does it change if air dr wyh5ee:+z 6x s7+y9tr0z9tkeh,g ffriction is ignored?

  As a freely falling object speeds up,isk6 r+en9 )7siep +nt what is happening to its acceleration, how does it cs 6insn+p+r )ikt7 9eehange if air friction CAN NOT be ignored?

  An object that is thrown1kfvf6pxukz4:ly y,q8 vj--j vertically upward will return to its original position with the same speed as it had initially if air resistance is negligible. If air rjl,fp z6yjk- 4 ykqx-1fvv :8uesistance is appreciable, how will this result be altered?

  An object can have zero velocity and nonzero az9t f4nrv./dyaw : x2fcceleration at the same time.

  An object can have nonzero velocity and zero acceleration at the o-e0mt o g: .lty.iv6bsame time.

  An elevator moving from the second floor to the fifth flof15 tb-mxz7.x vj8bvyei0 y (lor making no stops along the way has zero acceleratio5xmybvt 1- 0x. b8yif( ev7zjln all the time.

  A rolling ball moves0om0w)ii*n a m from $x_1=2.8 \mathrm{~cm}$ to $x_2=-5.5 \mathrm{~cm}$ during the time from $t_1=0.9 \mathrm{~s}$ 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 $t_1=-2.4 \mathrm{~s}$ is at $x_1=2.1 \mathrm{~cm}$ and at $t_2=4.0 \mathrm{~s}$ is at $x_2=8.1 \mathrm{~cm}$. What is its average velocity?  (数值)  $cm/s$

  A person jogs eight complete laps around a quarter-mi.slgw5xm35 -tj ll9 hele ($1 \; mile = 1609 \; m$) track in a total time of 8.3 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 109 m 74s)2z thhuxx ey +2;hgj p1ejaway in 13.3 s. It then turnse2u hyg; t zp)s2jhxhe41 j+x7 abruptly and gallops halfway 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 frybdc23 uy44f 5-f zjbng47ebc1evv. m 1 (lkioom $12 \; m/s$ to $23 \; m/s$ in 4.1 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 fro brgf4j t93d5.u pbpi/m $17 \; m/s$ to rest in a distance of 65 m. What was its acceleration, assumed constant?  (数值)  $m/s^2$

  A light plane must reach a -y2:ae pdi.ur speed of $28 \; m/s$ 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 can burst oucny 15sv81vofr54m(s6n d ypc t of the blocks to essentially top speed abouy8(s fv c4nmcno 5s1561rydvpt $10.4 \; m/s$ in the first 12.5 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 frozm5kxq,. cub2 m a speed of $21 \; m/s$ to rest in 5.61 s. How far did it travel in that time?  (数值)  $m$

  In coming to a stop, a car leaves skid marks 9:8g;oyumy;j+j0t mg- tc(j qk 2 m long on the highway. Assuming a deceleration of km+ty c(:tug 0oym;jq j8gj;- $7.00 \; m/s^2$, estimate the speed of the car just before braking.    $m/s$

  A car is behind a truck going-y)wv8 0s bbdz $25 \; m/s$ 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).    $m$

  A runner hopes to complete the 10,000-m run in less than 30.0 min. Aftebp im/dkk0weufa) 3c5 v2-o;r 80u .tuf +cewlr exactly 27.0 min, there are still 1100 m to go. The runner must then accelb.tw2p38;)uevu0iffmkl5oe -w c ur0dk a/c+ erate at $0.20 \; m/s^2$ for how many seconds in order to achieve the desired time?    $s$