Suppose that an object travelsnsvgx7ze2 1 ;n from one point in space to another. Make a comparis 12e7z;n gvsxnon between the displacement and the distance traveled.

  When is the average velocity of an object equal to thek( :vvko da8r; instantaneous velocity?

  A new car manufacturer advertises that their car can go pxciy . fxjpj 7n:l(-hjca-i-r)qx78 "from zero to sixty in 8 s". This is a x j7--y7rxixncj)(8p-jc ial hqf:p. description of

  An object moving in the +x axis experiencyli;sm 3xrezfson hryzl okx:7v 8t/ u23/.+ 2es an acceleration of $2.0 \; m/s^2$. This means the object is

  Suppose that a car traveling to the East (+x dir3n +l;vj8t tpbection) begins to slow down as it approaches a traffn3p8 ;bt lvj+tic light. Make a statement concerning its acceleration.

  Suppose that a car traveling to the Wmp2w-q. 9tsss0)qf rl3)*r u my zqze1est (-x direction) begins to slow down as it approaches a traffireq l )z p* .szmfuqrts-s319)yqwm 20c light. Make a statement concerning its acceleration.

  Suppose that an object is moving with a constant velocity. Make a statemens 3f9et8 oc6iaal8 nh5t conaeihctol889 s63fa5ncerning its acceleration.

  If the velocity of an object is zero, does it mean th4q7bmzr9wg r7(wrdtp0j e40*a *zpjxvac 3 -hat the acceleration is zero? Support your answer with an examp4qmap3( rc4p*g7vdt-whb*0ajj7zrx w 0ze r 9 le.

  Can an object's velocity change direction when its acceleration is cotpe ,xs gp5k z)r-eb.4nstant? Sup -r.e s5ep)zbtpx4g k,port your answer with an example.

  Suppose that an object is moving with constant acceleration. Mys;csx ,8sj6u ake a statement concernin8 j suxc;,ys6sg its motion with respect to time.

  Can an object have increasing speed while its acceleration is decreasing? Suppm q snu ocy6:gf5+3i6xort y5s ogm3 i6y+uxfnqc:6our answer with an example.

  Suppose a can, after an initial kick, moves up along a+ieqk vg6k td 7i+ 4enyx2p56m smooth hill of ice. Make a statement concerning its accep x65tkq dg e2kv+7i ym+n6i4eleration.

  Under what condition is average velocity equal to the average of the 2fd ypwq-(;:cw3evx jobject's initial and fi;3(wcjfy:pwe d 2-xqv nal velocity?

  Objects A and B both start at rest. They both aa ,* l;qh0ohac,jf+ty ccelerate at the same rate. However, objecholc + f,aqj, h0;ta*yt 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 rese58rq a:q,lftt. They both accelerate at the same rate. However, object A accelerates for twic: , 8leq5rtqafe 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 falls in the absence of friction, +k2 7(hqec ,pkglmmm,which of the following is true concerning its motim +pkl(mcmhq,7 ge, 2kon?

  When an object is released from rest and falls in the absence 706.d9z)oh vi 8ygb2w 1 ejukeru6upkof friction, which of the follo2di)ub1vuj80r ge u6 k ek6owzhp7y.9 wing is true concerning its motion?

  Suppose a ball is thros e8;,k8 rfw;kay,oyrwn straight up. Make a statement about the velocity and the accelera ;;w fkyar8ysk ,r,8eotion when the ball reaches the highest point.

  Suppose a ball is thrown straight up. What isa2 pupr9pm9 6h its acceleration just before it reaches itrm9ph6pa 9u2 ps highest point?

  Suppose a ball is thrown straight up, reaches a maximum height, then falls *36bbjmtz+5a p:5f,jjm bijr to its initial 63bjrbf+i tm:5zj5jm a,p b*jheight. Make a statement about the direction of the velocity and acceleration as the ball is going up.

  A ball is thrown straight up, reaches 9i(xy6 6pixx *dcqes1hs l3m7a maximum height, then falls to its initial height. Make a statement about the direction of the velocit iyes3d69ip1qc h lmxs (*76xxy and acceleration as the ball is coming down.

  Suppose a ball is thrown downward in the absence of air resistance. Makerk)nqjmy, 5lnp/q/9 q6r1vt r a statement concerning its accel1qnnrqmt v9rj/6 r 5,/kpqly)eration.

  Suppose a skydiver jumps from a high-flying plane. What -c,rk u-ycvugnd( 1:c is her acceleration when shcy,cnvu dckg1 -r:-u(e she reaches terminal velocity?

  A ball is thrown vertically upward wi qtc4 eegtdpm0cujhs5y1j0/ 3 ep9c4+th a speed v. An identical second ball is thrown upward with a speed 2v (twice as umycj ct/e4t e1+ghpdc05p 943sqje 0 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 buil)b7iklp ;ivc) k4si -fding. One second later, ball B is dropped from the same building. As time progresses, the distance betwep))kfc-7l ;vkib is4ien them

  Ball A is dropped from the top of a building. On 7kdeu5iw9bc,s sp85 z2ftia4e second later, ball B is dropped from the same building. As time progresses, the difference in their sp4tad2,c 5f5wpk7e8i9s isu b zeeds

  Two objects are thrown from the top of a tall building. One is throwiv/ :k- lnscv*n up, and the other is thrown down, both with the same initial speed. What are their speeds when they hit the l nk vi*s:c-v/street?

  A brick is dropped from the toe ,8:pcdv433in i zdvsp of a building. A second brick is thrown straight down from the same building. They are released at the same time. Neglect air e3dsc,v4 8zdpi: vn i3resistance. Compare the accelerations of the two bricks.

  An object is moving with constant non-zero velocity in the +x axis. The pos/y,e,28rf yg khq,ln*z+oundition versusgd rnkuhy, eqyzf+/82, *ln ,o time graph of this object is

  An object is moving with constant non-zero acceleration in the +x axisuyyi ss:35ed -nq(r-s . The posii(y:esyq 3s n d-5rus-tion versus time graph of this object is

  An object is moving with constant non-zero velocity in the +kv lqdd90 (d :fi;2 1z6ylltrqx axis. The velocity versus time grtl(9kdfq zd:0d1ll2 q y6 rvi;aph of this object is

  An object is moving with constant n t rdxc95t4-abi4ov s:on-zero acceleration in the +x axis. The velocity versus time graph of 5a4x:vtrso i-9 cbt4dthis object is

  The slope of a positio*c( 7tqu wc+/-e1(aq(drty majo0x jom.wzb 9n versus time graph gives

  The slope of a velocity vers+epr1cxqil bvr80e2nu ) 5yy7us time graph gives

  The area under a curve in an acu+ mez8 u2xt(c sipu+(celeration versus time graph gives

  The area under a curve in a velocity versus timjt gwf+)+s8w fxyb*l. e graph gives

  If the position versus time graph of an vueftp4:iw-71 2loern(a (cs object is a horizontal line, the object ira c(fes7u v2: nlopw-1(ite4s

  If the position vers2nqyce(v wi8h8u7mg :us time graph of an object is a vertical line, the object is ch7:g eywqmn2 8v8u(i

  If the velocity versus tg w4l x8o..m w er38tnk3r*: 4ohjqgxfime graph of an object is a horizontal line, the object helwx 8w8rn3r. .xq43kg4: g*foj tomis

  If the velocity versus tie skjj-1k2v8g* qhde3gce+ .e me graph of an object is a straight line making an angle of 30 degrees with the ti3*e cqe1jg.+e2vk ek 8hd-sj gme axis, the object is

  An object moves 15.0 m north and then 11.0 m south. Find both the distancezll zh2x94 (qn q:js.a traveled and the magnitude of the d(l:jnslzqx4 a2h.qz 9 isplacement vector.

  A boat can move at 30 km/h in still water. How long will it takq8b,d4yj i68o7 ivkdp e to move 12 km upstream in a river flow qi d78k4vyob,jd8p6iing 6.0 km/h?

  55 mi/h is how many 2 kc:un.uuzodg uopa36 7 52mnm/s? (1 mi = 1609 m)

  What must be your average speed in order to travel *zhzu) (.womas,skr d,d:v,r350 km in 5.15 h?

  A runner ran the marathon af 2j;s9 /dh.k og;)vy lm 9botp,coi*(approximately 42.0 km) in 2 hours and 57 min. What is the average speed of t ;9ktjpas9)2;mgdo c,v l.bi*o y/fhohe runner in m/s?

  A car travels 90 km/h. How long does it take for it to travel b+-r sf * utb3;3wjyjf400 km?

  A ly (light year) is theguk47*r 3 be22isww hu distance that light travels in one year. The speed of h2w3br ku*2iw e s7g4ulight 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 yoqnv u0 iqr7tj3.a97iaf dx t8* 9ks*oiu look to the side for 4.0 s, how far do you tratisi8if*7q doxva0ku. njr9q 7*39t a vel during this inattentive period?

  If you run a complete loop around an outdoor track (400 m), in 1bnox k ice)tv 7kxps7mmc w(1r-n45 0gr1cp3 +00 s, your average velocity ppnr7)tm4 xn-17m0 cogc ( cseik 15+bvwxr3k is

  A polar bear starts at the North Pole. It travels 1.0 km south, then 1.0 kmzjc9 gm6, o z7bggrs+3 east, then 1.0 km north, then 1.0 km west to return to its starting point. This trip take+mzrg6jz , g gc9b7s3os 45 min. What was the bear's average speed?

  A polar bear starts at the Nort9.ne;av df knslvz.wj*0 8*kq h Pole. It travels 1.0 km south, then 1.0 km east, then 1.0 km north, then 1.0n0qs*;d 8f .v9*nkv .eljzakw km west to 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 mi/h for 110 miles. It the6(mruo , pgm3an starts to snow and you sloompu3g(r6am ,w 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 v2,wr,)x;xuott 5 keoyoapjm j,7( )wand 160 km at 100 km/h. What is the average speed joy,rwe k),t,v2u7;t)xmw(jx pa 5oo of the motorist for this trip?

  A motorist travels for 3.0 h at 80 km/h an b9ya- esv8irf3 h eqln.,*rh0d 2.0 h at 100 km/h. What is her average sp0 8ree.v*n a l ybf-rq3si9h,heed for the trip?

  An airplane travels at 300 mi/h south for 2.00 h and the-4m-kquea51u/ tpg 2ja7gk f mn at 250 mi/h north for 750 miles. What is the average sp5/gmgmkq k7u2u-pfeaa41t j -eed for the trip?

  In a 400-m relay race the anchorman (the person (6g4y to;ug 6el8eyb9x 6 xvuowho runs the last 100 m) for team A can run 100 m in 9.8 s. His rival, the anchorman for t9xbgyo4y8(u l voxg6t u 66;eeeam 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 that the team A runner not lose the race?

  A car decelerates uniformly and comes to a stop after 9 s. The car's average:y8o euu:p4. i im ua0ozux,:y velmpieu ,4z. u 8 ua:xy:y0oiou:ocity during deceleration was 34 km/h. What was the car's deceleration while slowing down?

  An airplane increases itsq t9cl/9gptn4 speed from 100 m/s to 160 m/s, at the average rate of gtq/ p49ntcl9$15 \; m/s^2$. How much time does it take for the complete increase in speed?

  A car traveling 60 km/h accelek nhzy4dhp. a(ogf:t0 7 iz+x25put1erates 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 acceleratrm0l50b7n mc )pn3v fues 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. p2x .f2k nkiwln91*cv It then speeds up with a constant accelerationi.x9fpc *ln w2v2k1nk of $2.0 \; m/s^2$ for 15 s. At the end of this time, what is its velocity?

  A cart with an initial velocity n0iqkd-qhd 8 h j8vw):z3;kv tof 2.0 m/s experiences a constant acceleration o: kj883-kitd v )z0nvdw hq;qhf $4.9 \; m/s^2$. What is the cart's displacement during the first 7.6 s of its motion?

  A bullet moving horizontally to the right (+x direction) with a speed of 4x9kq(jp:s2s :tode6 jge/ o4 rzu u)o.78 m/s strikes a sandbag4z: j eotr/g.o qjo :(dp2sueksu)69x and penetrates a distance of 94.44 cm. What is the average acceleration, in $m/s^2$, of the bullet?

  A jet fighter plane is launched from a catapult on an aircraft carrier. It o0 y)h +ctlyrebf-ze u e*:*k/reaches a speed of 42 m/s at the end of the catapult, and this requires 2.0 s. Assuming the acceleration is constant, wh0t +ekfcuhrol*b)yz ee -/*y:at is the length of the catapult?

  A car starting from rest moves with constant acceleration of t1syp5wjt7d/ i 1g wh*$2.0 \; m/s^2$ 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 2a r x9q r(p)hjc93b0tc00 m. What is its average accelerartbcap j99)qc3(x0r htion?

  An object starts from rest and undergookak vh-+sz3 1es uniform acceleration. During the first second it travels 1.5 m. How far will it tr1kvkhz os+3- aavel during the third second?

  An object is moving in a straighe )x4x+rdfl7 ut 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 lfx7)xd+e4ur move during this time?

  A car starts from rest and accelerates )/xx14avr5jzl qd,qg 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 deceleratez cir +re0;z8q3 vq;p(y.khyu 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 turns green, a car that has b 5*zvwtus5g, 1 fr-tuo p/lc-eeen waiting at the intersection starts ahead with a const5 /str,uc1 tow-g f p-5zeu*lvant 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 planet X)yn1.yejltq0 ioz f)* where the acceleration )ynf0*1q ot.z ie lj)ydue 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 planet X g prx*6 wymsmg0+dm,sv el 97,where the acceleration due to g0 s y7m,g+e*9pxgr6dl,vsw mm ravity 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 ofni30j+ us-jnv 15 m/s on the surface of planet X where the acceleratiosv ju n0-ijn+3n 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 surface of planet X dz7 3)rjv- q 7poc/-akz+l lht+6 jmnlwhere ql+73tdo7 na+ l) -czl mv/k6zhjj-prthe 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 k:np/.(8 z na*pipfswa o9i*h -q:kppusually greater than 0.10 s. If your friend holds a ruler between your fingers and releases it wqonkz:.n ipa*k:p (w9phi*-8ps/a pfithout 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 itsi5;gaa 7h( u5j: xqwwg velocity after 3.00 sai u5:wgjg(75;ax qhw ?

  A bullet shot straight up returns to its starting point in 5 s. What w+1x, xx0w ufzis the initialfz0x ,+xwwx 1u speed of the bullet?

  A ball is thrown straight up with a speed e;xs1ns:e yy4m(q d;eo9h9lyof 36.0 m/s. How long does it take to return tom9e(y:14q; h s ey;9olsydnxe its starting point?

  A ball is thrown downward from the top of a buildik jh rw 9pbbw;q+z)s-3ng with an initial speed of 7 m/s. It strikes the ground after 7.1 s-r9jz;wpb)q shk+b w3. How high is the building?

  A ball is thrown straight u/ dd bzcw*c/x + ti0dmel7s;o)p with a speed of 30 m/s. (only fill in numerical value in the tm;*cc wdbs ) z7l0oddi e+x//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 st 7u -i ufc6e,p:d)ui4w0uoalsvk)y8craight up into the air with a speed of 48.3 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 7 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 7.0 m above the point of contact a second time.  (数值)  $s$

  In Fig. below, what *1zyh38mp+t 3jaq rtmis the velocity at t = 1.0 s?

  In Fig. below, what is the vi :b zo7lh.7 yhb:2ibdelocity at t = 2.5 s?

  In Fig. below, what is the velocity at t =oci7c6 gg4at() (yq kn 4.0 s?

  In Fig. below, what is the veloci57v t6hbip/p*b;w;a 6wrq p;rmh,buity at t = 5.5 s?

  In Fig. below, what is the average velocity from 0b.,gxjs8oz k0 to 4.0 s?

  In Fig. below, what is the average velocity frog 0bwaw ;v:7 avnp +t3fu x.rg2z/wjw)m 0 to 6.0 s?

  In Fig. below, what is the acce-q e t;w10qfchy6:uigg,fn1 wleration at 1.0 s?

  In Fig. below, what is the acceleration at 12ox9 lan* m.xgx 2n8ldgkyppi0b4x/ 3.0 s?

  In Fig. below, what is the average acceleration from 0 to 5.0wth s0.yjmr ,*k-uu9h s?

  In Fig. below, what is the ave mlc8uivqa8jz8g) wp3mr*8e 5 rage acceleration from 0 to 8.0 s?

  In Fig. below, what is thexyecjvo)h . j4 )hk,( sb;pp0y displacement from 0 to 8.0 s?

Does a car speedometer measure yadci6n(um en138u5mgp;sh0 speed, velocity? {speed|velocity}

  An object can have a varying speed if its velocity is ecql*cd5em 2xam( +b2vnr3 ,wconstant.

  The velocity of an object can be negative when its acceleration is posi ykadsh+l+ h7(tive.

  If one object has a greater speed than a second objec(rrudn , bcjl-s zg.l8h r98d3t, the first must have a greater acceleration. b- d,j3cu.s9(lg nhrdrzl88r

  Two cars emerge side by side*n)v9boo wy*p from a tunnel. Car A is 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 /a6etpvin tu55i; dt5as its acceleration decreases.

  A baseball player hits a foul ball strag2 gc5 s ba-s4ln55e89yfo/1 g8kwycxtoi c;yight up into the air. It leaves the bat with a speedy4yfb/ygc go9 a; c 8c5tne8s2 l1sx5gw5-koi 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 j3bdm az,ncld;l1 7*bup, what is happening to its acceleration, how does it chanz a l,d3;n7m*cbbl1 djge if air friction is ignored?

  As a freely falling object speeds up, what is happen1:zrsdz 0(g hhing to its acceleration, how does it change if air friction CAN 1s zzg:d (hh0rNOT be ignored?

  An object that is thrown vertically upward will return to its original positiono2ng0az * o1ir am6bd) with the same speed adm a)*2zn r1ab6iogo0s it had initially if air resistance is negligible. If air resistance is appreciable, how will this result be altered?

  An object can have zc4-y--r us hju mc+/nzhxhju8 zpb)jx2+cn9/ ero velocity and nonzero acceleration at the same time.

  An object can have nonzero veloc0s-vt c1; z+ebjhgkb/ity and zero acceleration at the same time.

  An elevator moving from;h m;*plpiv4 fbv:1 pl the second floor to the fifth floor making no stops along thevpppl ;vbfl1h4 :mi* ; way has zero acceleration all the time.

  A rolling ball moves f:7 xnah)0fgfa rom $x_1=1.9 \mathrm{~cm}$ to $x_2=-5.3 \mathrm{~cm}$ during the time from $t_1=2.3 \mathrm{~s}$ 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 $t_1=-3.8 \mathrm{~s}$ is at $x_1=2.0 \mathrm{~cm}$ and at $t_2=4.4 \mathrm{~s}$ is at $x_2=7.7 \mathrm{~cm}$. What is its average velocity?  (数值)  $cm/s$

  A person jogs eight complete laps around a)ex6fswpmbrrd26 ald5 89 n6l quarter-mile ($1 \; mile = 1609 \; m$) track in a total time of 7.7 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, 4gypq/ b)vwmu .s ad (aa.8r 1jsf(gkt dry498moving 91 m away in 9.8 s. It then turns abruptly and gallops halfway back in 4rdru/va 8g9a pwsa g( by(q stk8m)4d1.jyf .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 frc *8i9i/r gexxom $11 \; m/s$ to $25 \; m/s$ in 4.2 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 n rwzn4,acz.2 q/s5os$19 \; m/s$ to rest in a distance of 75 m. What was its acceleration, assumed constant?  (数值)  $m/s^2$

  A light plane must reach a speed of cb8)4 fd00zzy38tsv 4zi c rcw$33 \; m/s$ for takeoff. How long a runway is needed if the (constant) acceleration is $2.8 \; m/s^2$ ?  (数值)  $m$

  A world-class sprinter can bursma c3. f xhyo3:1jo:nat out of the blocks to essentially top speed about n3x fojc3ymo .ha::a 1$11.3 \; m/s$ in the first 11.5 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 unif,o /j2s nhjhz8ormly from a speed of $17 \; m/s$ to rest in 5.21 s. How far did it travel in that time?  (数值)  $m$

  In coming to a stop, a ca8ux n1ih5vk 0qr leaves skid marks 92 m long on the highway. Assuming a deceleration ounk8v0 i15xhq f $7.00 \; m/s^2$, estimate the speed of the car just before braking.    $m/s$

  A car is behind a truck goingj/y6k 1 *ft7f86yn c 2bkanrnhdeg(2q $25 \; m/s$ 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).    $m$