Suppose that an object travels from one point in space to another. Ma f zv.eturut5)9deq-4ke a comparison between the displacement and the diur e vdu)etzf5tq4-9.stance traveled.

  When is the average velocity of an object equal to the instantaneu(( iztv(r9 75 nyqj-awow.jy ous velocity?

  A new car manufacturer advertises that their car can go "from ze/w /fx85lwnq/u0q+jwpi 7l ztro to sixty in 8 s". This is a descripz8xwl+ i q/750tj/wwqp/ lfuntion of

  An object moving in the +x axis experiences an accelerat qn4h s-t.ysay*j7kndk7j ,8uion of $2.0 \; m/s^2$. This means the object is

  Suppose that a car traveling to the East (+x direction) beging/hkg 3( dhdl3*5 :ey+ggnaui s to slow down as it approaches a traffic light. Make a statement chgaydi n:3e3glh /d( 5kg+g*uoncerning its acceleration.

  Suppose that a car traveling to the West (-x direction) begins 50qkfjfm s qel00* sm/to slow down as it approaches a traffifmj50kql 0e0 */fms qsc light. Make a statement concerning its acceleration.

  Suppose that an object is moving with a constant velocity. Make a statemar.t7* wjy6p j :6eo: hzh+xerent concerning its aj7h: r6o:wyzjee . a+6htrx*pcceleration.

  If the velocity of an object is zero,z)qdjos/ s(8 f does it mean that the acceleration is zero? Support your answer with azss8j f(o/d )qn example.

  Can an object's velocity change direction when rv(4 i-zhr /((*rndga pi5r uey(3lsmits acceleration is constant? Suppor( rl3psri(mdzi*(re(y hnua v/g45r-t your answer with an example.

  Suppose that an object is moving *pgut j ,/ b7m9c(o nnpfvm;n0 0iklx1with constant acceleration. Make a statement concerning its motion with respect to timeb0cl t*7mfng9up0(in mxo/j ;n, kp1v .

  Can an object have increasing speed while its acceleration is de0k( zbp ix+ef)6hsv a3sfs s;3creasing? Supportkp z3s s6h)vsefaisx 3(b+0f; your answer with an example.

  Suppose a can, after an initial kickffs; jo2* o+ fmg3cgk), moves up along a smooth hill of ice. Make a statement concerning its acceljg+fo3f2;ckm fgs *o )eration.

  Under what condition 2768;gugv opvjucwfk-w cqm3 (l(ixl62in0 ris average velocity equal to the average of the object's initial and fi7vqg( flu32mwik2 rlgvx u6n-;wc0(cpjo6 8inal velocity?

  Objects A and B bothdv+dj**wkbzqrb8( x3b()m lz9mrba 1 start at rest. They both accelerate at the same rate. However, object A accelerates for twice the timb awxr (b(r* )lbz1qb jdv+zkmd38 m9*e 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 bothf5nbzdvz+zs,3n -39ii-k h gj accelerate at the same rate. However, object A accelerates for twice the time as object B. What is the distance travelhnkzg-v9iz3 3dfz j s-,bi+5ned by object A compared to that of object B?

  When an object is released from rest and fallpkl* 6 mgy)pcr12udj g5;0tib s in the absence of friction, which of the followi kl2gp y1t65pmrd* ); 0ibgucjng is true concerning its motion?

  When an object is released fgkl2+rnk2de:9j+eps w:4c gfrom rest and falls in the absence of friction, which of th:+psn l +:ej2k4 gek92gwf cdre following is true concerning its motion?

  Suppose a ball is thrown straight up. Make a statement about the ve*n(g7mlo2zwok ) w+shlocity and the acceleration when the ba*ow(g +)om7s k hzn2lwll reaches the highest point.

  Suppose a ball is thrown straight up. Whacoh7taxbxk :affd 4u( y6s9)/ t is its acceleration just before it reaches its highest4y7bkaa6 o/9 x tcsfhx)( fu:d point?

  Suppose a ball is thrown straight up, reaches a maximum height, then falls to 2;dvj;u+aesjng- om)6hg:9ht +tn t eits initial height. Make a statement about the direction of the velocityjshntoua-vht;6; n+e2j+ g :mt)9 dge and acceleration as the ball is going up.

  A ball is thrown straight up, re nl b.3onqv1gltixm+ t/5 :/xyaches a maximum height, then falls to its initial height. Make a statement about the direction of the veloclmn n/tgi1 b yv+. lt/3x5:xoqity and acceleration as the ball is coming down.

  Suppose a ball is throwncgcl+;avlm/n;q- q 4yhq2 idy 2fb+) o downward in the absence of air resistance. Make a statement concerning its ad /y qgv4)yo cafhl; i;qcm+nb+ l22-qcceleration.

  Suppose a skydiver jumps from a high-flying paw)rj 2o21fu/yi t,hrlane. What is her acceleration when she she reaches terminal velorai2hj) w1yr u,2ft o/city?

  A ball is thrown vertically upward with a speed v. An ide.lqa 2cg5zt1vu/e x:entical 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 vu2e. zt5x1ea/lqc: g 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 B2kram) i)lz11jt q-nndf/4d v is dropped from the same building. As time progr1fvkzir 4dan)d t2)l/1 m -jnqesses, the distance between them

  Ball A is dropped from the top of a building. One second later, ball B .hu1cf /*76dzeze czzis dropped froc*cu6zh/ zdz1 e7 zef.m the same building. As time progresses, the difference in their speeds

  Two objects are thrown from the top of a tall building. O t43 py.g*bmonqb*q,fne is thrown up, and the other is thrown down, both with the same initial speed. What are their speeds when they hitq,mb* pf.b3y4qgotn* the street?

  A brick is dropped from the top of a buildirpz wzbwov(+6wqa052 ng. A second brick is thrown straight down from the same building. They are released at the same time5p a2w +w6vzbwq0r( zo. Neglect air resistance. Compare the accelerations of the two bricks.

  An object is moving with constant noq4ruzlzh75 rw h3.4r zn-zero velocity in the +x axis. The position versus time graph of this objezz 4.7qr4 3lurrh5wzhct is

  An object is moving with constacrl 0 xh k1wq3m422amont non-zero acceleration in the +x axis. The position versus time qc0km2xh om4rw a32l1graph of this object is

  An object is moving with constant c baahye7 x6d-599dvgnon-zero velocity in the +x axis. The velocity versus time grxdaa6v-95dh9 gcb 7eyaph of this object is

  An object is moving with constant non-zero acfq5(ea , ua+wt )g,xwpceleration in the +x axis. The velocity versus time grap,t,(qw w5gxa+ f)ea puh of this object is

  The slope of a position versus time graph 0 olu*9idh8zcc * rbozaldp18u* r6x7 gives

  The slope of a velocity versus yzq*k y.dw 8,stime graph gives

  The area under a curve in an acceleratio hb: to4n,bq*wn versus time graph gives

  The area under a curve iv acr +x3r /8v+f-d xv5wrj.ndn a velocity versus time graph gives

  If the position versus time graph of an object is a hou,pqez t2s 12fwdo j:,fl.x.nc od/n8 rizontal line, the object .t wl x2nn1 fqs,d/8zefj 2:oud.,copis

  If the position versus time graph of an*u0p15r xhvvi object is a vertical line, the object is*5hr 10v ipxvu

  If the velocity versus time graph of an object is a horizonpv wquj5a 7,b+tal line, the object q,j5u +v bw7pais

  If the velocity versus time grcp*aa*; 5rz; u qb o:r(7e enuj0w0mfqaph of an object is a straight line making an angle of 30 degrees with *empru;5a*zc 0: buoqe 7r w;(q0nfajthe time axis, the object is

  An object moves 15.0 m north and then 11.0 m south. Find both the distancwjvl3w43m/tgef ci v6+(hp ,n e traveled and the magni(cp, w3nh+e / ltwmfgvij6v34tude of the displacement vector.

  A boat can move at 30 km/h in still water. How long will it take to move 1t +pp:1pv+mxfce-bp *2 km upstream infv t-mp+x*bcp+ ep: 1p a river flowing 6.0 km/h?

  55 mi/h is how many m/snxc sd5oej*e68fy p21? (1 mi = 1609 m)

  What must be your averaj*7ce2 k; p vx2yxsyvlh5xjy .q*0h*dge speed in order to travel 350 km in 5.15 h?

  A runner ran the marathon (app1 hg ;po p7wzp81y+yieroximately 42.0 km) in 2 hours and 57 min. What is the average speed of the runner in m/s? gi pyhyowep1+p78;z1

  A car travels 90 km/h. How long do2* ebh,s 7b(ytm-r umbh/u fs;es it take for it to travel 400 km?

  A ly (light year) is the distance that lightc5h wr:,wzg5j travels in one year. The speed of light chj,5 5 zgrw:wis $3.00 \times 10^8 \; m/s$. 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 straight2 .rtl b yg5vsmj(;te9 road and you look to the side for 4.0 s, how far do you travel during this.y(r9 v g;t52jelsmtb inattentive period?

  If you run a complete loop around an outdoor track (400 m), in 1009p3guw,u8g, wzry4ad(4y0f0d- y 5 c nzifpls s, your average ve uuzg4 ifraws, w 59l-4ycn0py80 dp(y3zdf,glocity is

  A polar bear starts at the North Pole. It travels 1.0 km sou5c3ln w5)ormxh -t fh4th, 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's average spl x-wt )3 n4om5r5fhcheed?

  A polar bear starts at the North Pole. It travels 1.0 ns6j j olk::qt(*-igl0fb9gs km south, then 1.0 km east, then 1.0 km north, then 1.0 km west toi-6jktlj *(g 9n:o:gbqss0fl return to its starting point. This trip takes 45 min. What was the bear's average velocity?

  You are driving home on a weekend from school at 55 mm8vmy7ax pq4o*aoj 9(i/h for 110 miles. It then s8 p aoao(yxjm9*v4 m7qtarts 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 school?

  A motorist travels 160 km at 80 ,zf 70z u.mjdxkm/h and 160 km at 100 km/h. What is the average speed of the motorist for thisx7m0zd ,f zju. trip?

  A motorist travels for 3.0 h at 80 km/h and 2.0 h at 100 km/h. What.2f-k0 a 5qezv+qabfc /l dj(a is her average speed f f/zcjaq vd.e+(q5 aa bl-02kfor the trip?

  An airplane travels at ,jx9k ) wyl3vy300 mi/h south for 2.00 h and then at 250 mi/h north for 750 miles. What is 9kyy3,l v xjw)the average speed for the trip?

  In a 400-m relay race the anchk6 r*q kw 8hbcq-zi.zpz u 1v1hg(),mborman (the person who runs 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 hvk(p) c 1g8kw.zhmbr6 *qbzq1 u-z,iteam 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 aft.m sq n9mpi4n3er 9 s. The car's average velocity during deceleration was 36 km/h. mm 3 q4pn9is.nWhat was the car's deceleration while slowing down?

  An airplane increases its speed from 100 m/s to 160 m/s, zw/4j g kjdi)h024n hokjh /e6at the average rate of z new j/h h)6g44i0jdkjhk2/o$15 \; m/s^2$. How much time does it take for the complete increase in speed?

  A car traveling 60 km/h accelerates a. wcnngmf * -d3n aqx9g0xr*/it 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 , b4h w.rhv3a u6)bkhsand 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 j-zqbtg e9o70:,hqx fra/9yeconstant acceleration o x9 a79q0tfj/q-gy,b: rozh eef $2.0 \; m/s^2$ for 15 s. At the end of this time, what is its velocity?

  A cart with an initial velgnyd:8fvj bl ag+3bp c0 t1a8,ocity of 3.2 m/s experiences a constant acceleration ofygn8 ,jv g+1fd3pbl 8t0:bcaa $4.6 \; m/s^2$. What is the cart's displacement during the first 9.6 s of its motion?

  A bullet moving horizontally to the right (+x direction) with a speed of 562 kzmkotmao3 +,sa1dx/+6sf x3 m/s strikes a sandbag and penetrates a distance of 90.37 cm ako/3t 6m1fxk,s+s+3dx oazm. What is the average acceleration, in $m/s^2$, of the bullet?

  A jet fighter plane lq2,pr rxhuwvc))o 55 is launched from a catapult on an aircraft carrier. It reaches a speed of 42 m/s at the end of the catapult, and this pcq ror) hu)5,52l wxvrequires 2.0 s. Assuming the acceleration is constant, what is the length of the catapult?

  A car starting from rest moves wit32 zqv*p*zj5edw y5y dh 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 in9.;qz*p u; vf ni ej7)5syeaan a distance of 200 m. What is its average acceleau. ae;e9s7fn)ivy np j qz*;5ration?

  An object starts from rest and undergoes uniftinds5/scr2j1 v. z q9m6+j jy;btv3form acceleration. During the first secfqj9;c3mvs yzs5vi+1 t dj2rt b j.6n/ond it travels 6.4 m. How far will it travel during the third second?

  An object is moving in a straight line with constant accelw 3p,xf+ek4ukeration. Initially it is traveling a,4uxkp+k 3wfe t 16 m/s. Three seconds later it is traveling at 10 m/s. How far does it move during this time?

  A car starts from rest and accelerates uniforml3eik90zeq(ig8k s ;eillr,z )y 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 phqo uym75o 7-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 travrmb8y8l 70hd+- cdh*r:hxck ffic light turns green, a car that has been waiting at the intersection starts ahead with a constant acc+-cdh :rlcm8* vyb78hd0xhkreleration 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 wi+;p)fi78kiq4 w pfgtycr p+e5 th a speed of 12 m/s on the surface of planet X where tr4)tcfe+w+ipf7p 5 kg py;qi8he acceleration 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 k ,nmb()jy5kb speed of 12 m/s on the surface of planet X where the acceleration due to grabjym5kbn () k,vity 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 of planet i1dk .y o0vh1c85//7 kvtuojdo hqut7X where the acceleration due to gri8ocuq0jtd5hku oo d7h//7v.1ytv k 1avity 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 surface of planet px xh v:q2r r50od4, jhy8osi4X where the acceleration due to gravit4ro q, ds x:x hph0vyr852i4joy is $3.5 \; m/s^2$. What is the speed of the object after 8.0 s?

  Human reaction time is/9 ;gd (ri:tsfb9cxw h usually greater than 0.10 s. If your friend holds a ruler between your fingers and releasftd:/ iwb;9 hx (gsrc9es it without warning, 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 .qgvbp2w7+ z5sa1g )veuux8i 3.00 58xuwzv.uv2b 1e+ )iggqa7p ss?

  A bullet shot straight up returns to ig.av 3)u9cigp 6ayy.dts starting point in 15 s. What is the initial speed of the b.9ay.3yg )g6iacuvpd ullet?

  A ball is thrown straight up with a speed of 36.0 m/s. How long d mjv8dbyrn(4 n:qr /e+oes it take to reqnrbry : 8(j4mve+d n/turn to its starting point?

  A ball is thrown downward from the top of a building with an initial s01gxu8yfnm . yu5ej cc7k r bvb8h21c,peed of 8 m/s. It strikes the ground after 3.7 s. How high is the8,1517ycuj0gmvb .rcy2e k8 b cfx nhu building?

  A ball is thrown straight up with a speed of 30 m/s. (only fill in numericala +41 tcpjrhk/0fzkv: value in the blp+ft a vj/r0k:c 4zkh1anks)
(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 .+ 6xz :pfqco shwq;r3mmw0 y:49.2 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 velocz;mw99v(lid idx4w 9;ho5jrwyyl8kw/ *q3q w ity at t = 1.0 s?

  In Fig. below, what is the vb 5y hkfqptf7s+g*d30 elocity at t = 2.5 s?

  In Fig. below, what is the velocity at t =4z 4a 6ektv(jywa 6,wd 4.0 s?

  In Fig. below, what is the velocity at t cj qg 1 6+55zr.obf**mchjbostr.m n0= 5.5 s?

  In Fig. below, what is the average velocity from 0 to 4yv y1g v)dq)1ny) g2zr.0 s?

  In Fig. below, what is the average velocity from 0 to 6.0 er-n/ zje+b6 qs?

  In Fig. below, what is 01lv gn, 9d0t l)iqioathe acceleration at 1.0 s?

  In Fig. below, what is the acceleratinr*w74u8 uvij)xsa y2on at 3.0 s?

  In Fig. below, what is thlijtl 66v13do ol: .oke average acceleration from 0 to 5.0 s?

  In Fig. below, what is the average acceleration from 0 to 8.0 s?gv hhq.eequ+9h ;-+z+p(sptj7 mqu ;t

  In Fig. below, what is tv4lhqnbye.rd 00 0 xm1he displacement from 0 to 8.0 s?

Does a car speedometer meas:6wqvt 22sdh bure speed, velocity? {speed|velocity}

  An object can have a varying speed if its velocity xwk:6i k wax1cxu576 wqn1ha;is constant.

  The velocity of an object can be negative when its acceleratio +2 gviu www)zc)w8/4zegqg0u n is positive.

  If one object has a greater speed than a second object n a+ky.:1ofex, the first must have a greater ya: +k.x1efon acceleration.

  Two cars emerge side by side from a tunnel. Car A is traveling wiu pzs7k6 (gs64ql dfo8 l8k,zbth 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 increasb u-svhig+ 8 zlru76z9ing in speed as its acceleration decreases.

  A baseball player hits a foul ball straight up into the au;ys sd6 zzm;,3hj09t8h gwme ir. It leaves the bat with a s s8j,dmhs ; zz he;y6g03utm9wpeed 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 g70 6qpt w57elnm+ 8jgc-nu gc ib,qk1speeds up, what is happening to its acceleration, how does it change if air frictg7jqpt gnmcl67kn1uige, 8-b 5q+c0 wion is ignored?

  As a freely falling object speeds up, whatzu v y0)l32o fp;d+mhn is happening to its acceleration, howvy+ozl dmu3 fn 2;)ph0 does it change if air friction CAN NOT be ignored?

  An object that is thrown vertically upward wil:h1a fwz;p, f/abz2 :+ason ufl return to its original position with the same speedoaasa :hfp zb/: 1;zw+2fun,f as it had initially if air resistance is negligible. If air resistance is appreciable, how will this result be altered?

  An object can have zero velocity and nonzero acceleration aj6pwjcyb5s el+05c,u t the same time.

  An object can have nonzero velocity and zero acceleratik uai(f3o6ao) on at the same time.

  An elevator moving from the second floor to p 93gj0u*kgunns418 yzd2typthe fifth floor making no stops along the way has zero acceleration8kdnus3 tzpg4 2gjpy*yun901 all the time.

  A rolling ball moves fvwdj( tja / kf10vpvmo i7.j.*rom $x_1=3.4 \mathrm{~cm}$ to $x_2=-5.9 \mathrm{~cm}$ during the time from $t_1=0.9 \mathrm{~s}$ to $t_2=5.8 \mathrm{~s}$. What is its average velocity?  (数值)  $cm/s$ (only fill in numerical value please)

  A particle at $t_1=-4.8 \mathrm{~s}$ is at $x_1=3.2 \mathrm{~cm}$ and at $t_2=3.6 \mathrm{~s}$ is at $x_2=8.5 \mathrm{~cm}$. What is its average velocity?  (数值)  $cm/s$

  A person jogs eight complete laps around a quarter-mvxpbaho, gc6.r ( pr72ile ($1 \; mile = 1609 \; m$) track in a total time of 10.1 min. Calculate (a) the average speed  (数值)  $m/s$ and (b) the average velocity    $m/s$

  A horse canters away from its traxahablw hm5okqi-a.81x:h-*z e6c6ra ) 7en niner in a straight line, moving 94 m away in 12.9 s. It then turns abruptly and gallops halfway back i heaeb1aq8xn-arho.h miw)k*c5n:6z7 -l6axn 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 frjqmft;(k :t-r)j* gnzom $12 \; m/s$ to $24 \; m/s$ in 5.4 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 9di7rnex (lyd- .*bya $23 \; m/s$ to rest in a distance of 82 m. What was its acceleration, assumed constant?  (数值)  $m/s^2$

  A light plane must reach a speed of7 xo1m+ . prmfni7um 6rr,yj2y $28 \; m/s$ for takeoff. How long a runway is needed if the (constant) acceleration is $2.2 \; m/s^2$ ?  (数值)  $m$

  A world-class sprinter can burst out of the blocks to essentially top speedlsz)am9f 4 mnw-*s5f7l t (hvj abou jl-s ffm5a4hmz s*wtv7n)(9lt $11.3 \; m/s$ in the first 13.6 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 dob9m yb1p*p- of $15 \; m/s$ to rest in 4.49 s. How far did it travel in that time?  (数值)  $m$

  In coming to a stop, acrt x naa5rf:/r g+*j: car leaves skid marks 92 m long on the highway. Assuming 5 xj:fnca+ t/a *rr:gra deceleration of $7.00 \; m/s^2$, estimate the speed of the car just before braking.    $m/s$

  A car is behind a tru) z:/temq;tgr ck 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).    $m$