Suppose that an object travels from one point ir e/t l u.eg1l0j5aa9,8wwqzkn space to another. Make a comparison between the displacement and the distance traveled.e e05tk zgwl19al/j,aq ru8.w

  When is the average velocity of an -) a,lru 9sdhuobject equal to the instantaneous velocity?

  A new car manufacturer advertises that their car can go btbu);mre6rqjwb8 /rvklv:+* j+ -ff"from zero to sixty in 8 s". This is a descriptmbrvl :+f)rr/t*b 8e bvwk;uj+fq-6jion of

  An object moving in the +x axis exxn*u9b ecl ef:1dtm :yqa5t 2+periences an acceleration of $2.0 \; m/s^2$. This means the object is

  Suppose that a car traveling to the East (+x direction) begins to slow downwt 94ghva,*lp as it approaches a traffic light. Make g , ahwpt*49lva statement concerning its acceleration.

  Suppose that a car traveling to the West (-x direction) begins to slow akr6 bt*(,(l 5ygqbx0+2 )pfb jdtzwxq )wt(wdown as itt )+ywag2d*(fb(b (pwkb,xxq 0 )ljz tq56tr w approaches a traffic light. Make a statement concerning its acceleration.

  Suppose that an object is moving with a constant velocity. Make a statement c1rm /ye5. k5orw*7w ljpwi6tnoncerning it6p r. l*j1/wwe5irko tw7ny m5s acceleration.

  If the velocity of an object is zero, does it mean that the acceleration is zero5ydtajrz+gztr 0wq3;/ d t4y 9? Suppor3yj ryt0 45rd; at/dztq wz9g+t your answer with an example.

  Can an object's velocity change direction when its accelerationc,d5ddy+:.wn mc xrl) is constant? Support your answer with al:.,c y+dwdx5 r)m dncn example.

  Suppose that an object is moving with constant acceleratl9kez:g h+:3tvwit y5t),lg 3 h,dghkion. Make a statement concerning its motion with respect to),g3ti9ktyh3l,hv gt5k dwzl + he::g time.

  Can an object have increasing speed while its acceleration is decrea*-w z5c2n1mcyn)jzjuzfek0 n s :zp;/sing? Support your answer ze wyj*z01/)j- 5sc unz mnc;k:f2z pnwith an example.

  Suppose a can, after an initial kick, moyj- 1fn(, l syjrgv9 e1v+: gqjzymc,/ves up along a smooth hill of ice. Make a statement concerning its acceleratg:ygc, j /evsyjrv 9+1fm jzyl, -n(1qion.

  Under what condition is average velocity equal to tb,q6h talco v9 c pm96p*g;ugt oa.l3 -wks)/rhe average of the object's initial and /k -;r vtlwgcmba9ou 6tpq 9), oc*g.phsal36final velocity?

  Objects A and B both start at rest. They both accelerate at the same rate. How9p n))8,0y rdiabkir wever, object A accelerates for twiw 9 )08bakiy)npdi,rrce the time as object B. What is the final speed of object A compared to that of object B?

  Objects A and B both starsaj04.j h5rh5ccl g(jk 4cn1vt from rest. They both accelerate at the same rate. However, object A accelerates for twice the time as object B. Whh( a4rc5h . gj0v4sckljncj51at 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 qd0e+1x5n (kw0khe8rd l*bmqg(d .cg of friction, which of theg l0cq h+5mn r k8kdewq(.dd0bx*e g1( following is true concerning its motion?

  When an object is released from rest and falls in the abajv yl6 hn/8w;sence of friction, which of then;6/8 hjvywla following is true concerning its motion?

  Suppose a ball is thrown straight up. Make a statement about the velo) ncnm/la.+xxcity and the accelxx)nc.a+m l n/eration when the ball reaches the highest point.

  Suppose a ball is thrown straight up. What is its acceleration just befor5illevkh;. c1oe1vw0cf j/cy m. eq1-e it reaches its h /hy 1e.i1wlmcoe. 0vf-ce5 ;j lc1kqvighest point?

  Suppose a ball is thrown stra3 :vxcripp b dq0w+13aight up, reaches a maximum height, then falls to its initial height. Make a statement about xvq +dw 0pi:a3bp13rcthe direction of the velocity and acceleration as the ball is going up.

  A ball is thrown straight up, reaches a maximum height, then fa nom 6)j.rzc7*;m g g,sdh(hn7a a9kmnlls to its initial height. Make a statement about the directiom*(o6h sghnc7. k9,d ;rm 7ngjazam)nn of the velocity and acceleration as the ball is coming down.

  Suppose a ball is thrown downward in the absence of abu4d )bl32/: wu jeoiuir resistance. Make a statemen4j2b):ie /uu wdol3 but concerning its acceleration.

  Suppose a skydiver jumps from a h7er 5wy.sg.dch ebk4:dh6 y3iigh-flying plane. What is her acceleration when she she reachehhw.de6rs7 d geb cy4ky3i. :5s terminal velocity?

  A ball is thrown vertically upward with a speed op;/wl c ve+9i zeui0/v. An identical second ball is thrown upward woe+zli; w/i 09vu/c epith a speed 2v (twice 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. Op7fqi* 8fk+fq4 9bw lhne second later, ball B is dropped from the same building. As time progresses, the diflp*qbqi7k94 8f + whfstance between them

  Ball A is dropped from the top of a building. One second la(6biht8h u u0oter, ball B is dropped from the same building. As time progresses, the difference in theiru0 t6ubhih8o( speeds

  Two objects are thrown from the top zfim54 /vphibgz6gh,jc8q3j(uk / 3iof a tall building. One is thrown up, and the other is thrown down, both with ujzi(z3 3/kg hhqjb 5g6,/f84mii vcp the same initial speed. What are their speeds when they hit the street?

  A brick is dropped fr /ezrw,z 2nq,bom the top of a building. A second brick is thrown straight downw/2q zer,n z,b from the same building. They 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 the +x e xr2yjr42,)hqwys eo)m4t k 5axis. The position versus time graph oee)jx 2km5ryqoy4t,2s h4)r wf this object is

  An object is moving with constanb)zgv2v-p 7xf b zt/sw/;7xv it non-zero acceleration in the +x axis. The position versus time gvv)7 /vgbx;i p2 z-bfw zx7/tsraph of this object is

  An object is moving with constant non-zero velocitl snpf 7fym+3v*g /o;ey in the +x axis. The velocity mofng;fv +l*73s y/epversus time graph of this object is

  An object is moving with constant non-zero acceleration in the +x axu/xbj4x9 ew- zis. The velocity versus time grap/u 49e-bj xxwzh of this object is

  The slope of a position versus time graphk6th c; 4mzng( gives

  The slope of a velocity ver;es (o)x iy.vrsus time graph gives

  The area under a curve in an acceleration versus time graphff;4jsb vrlkdc, - .14rgmt9w gives

  The area under a curve in a velocity versus time graph g.c,r6dt.he e*h u lez3ives

  If the position versus time graph of an object is a horizontal line, the objen(l/x)ct +z kact zcxn(/t+a) k lis

  If the position versus time moxt peq8rymc *jax vi)9a) 42a3nn49graph of an object is a vertical line, the object ispm4an*)tr av ) xjc9nq29m8ioyx3 e 4a

  If the velocity versus time graph of an object kpix amsp2: :cr wcl 639b2lr4is a horizontal line, the object p3 2c:wcsap l69m:r 2r4bilkxis

  If the velocity versus time graph of an object o:2a2gqd8lc1.s .k sfbi:a .o ehxm2 uis a straight line making an angle of 30 d..hosc.aikuxd f2 q:81l2o2mb:a esg egrees with the time axis, the object is

  An object moves 15.0 m north and then 11.0 m southgss )db5 7) zoveli7,umo tz72dv3fn/. Find both the distance traveledvm, edo7bi3/f ozl)7ss) zd2n5t g7vu and the magnitude of the displacement vector.

  A boat can move at 30 km/h in still water. How long will it take t d,jkwz*tnf: y4m67w lo move 12 km upstream inw, mw:fdtyk7l n6*4jz a river flowing 6.0 km/h?

  55 mi/h is how many y ;,xpa6f+n tum/s? (1 mi = 1609 m)

  What must be your average speed in*3ji lo5tbrv* order to travel 350 km in 5.15 h?

  A runner ran the marathon (approximately 42.0 km) in 2 hours and 5z9/ p4v7p6n)hwhnw wvrdj 6 n/7 min. What is the average speed ofphw9/d/vh 4wp n6rn6jwzn v7) the runner in m/s?

  A car travels 90 km/h. How long does it take for it to traveyjq3egc.5j:w r (b0 kfl 400 km?

  A ly (light year) is the distance that light travels in one year. Thehik 0( pdd(s8 8t8m 88lsrinti speed of ln880 dr(thsis8i(p i8tk8mdlight 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 straighrxnvdviap; 1d++7 pns. w 3k)-ldi*qrt road and you look to the side for 4.0 s, ho*ddr vx3s.+i p)-a n p7qwr+ldni;kv1w far do you travel during this inattentive period?

  If you run a complete loop a rcsz2v 9rc 7gn /3po:muxu+zk;a0fw- round an outdoor track (400 m), in 100 s, your average velocity-2wk:9r zpg;m +3von /uraf 0z xsc7cu is

  A polar bear starts at the Nortbpw23o9b uo /nh Pole. It travels 1.0 km south, then 1.0 km east, then 1.0 km north, then 1.0 km west to returbon wb/p9o u32n 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 e ahah9 )9:t3 ke3agay1.0 km south, then 1.0 km east, then 1.0 km north, then 1.0 km west to return to its starting point. This a3aeh:9e 9ga)ahy kt3trip takes 45 min. What was the bear's average velocity?

  You are driving home on*q +o2w;iqb.k wwtnwkt 4. 3cn a weekend from school at 55 mi/h for 110 miles. It then starts to snowt.; k qwb4nqwc2*w ot.3i+kn w 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 ka(. *8iez-f ,nborlgnm/h and 160 km at 100 km/h. What is the average speed of th o,*.eb z(ni rng8f-lae motorist for this trip?

  A motorist travels f(jz;ax +yl 6t1+luxe qor 3.0 h at 80 km/h and 2.0 h at 100 km/h. What is her average speed for the yeq6zxlt 1j la (+u+x;trip?

  An airplane travels at 3tj3.asyvl3 z o(6alt/00 mi/h south for 2.00 h and then at 250 mi/h north for 750 miles. What is the average speed foa/3 v3(ts jyl6. taozlr the trip?

  In a 400-m relay race the anchorman (the person who runsmb-0h 3m jrvyapkc.w:tpr3 2 : the last 100 m) for team A can run 100 m in 9.8 s. His rival, the ancpj3awt2.vcmrm p: br 30-kh:yhorman 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 that the team A runner not lose the race?

  A car decelerates uniformly and comes to a stop after 9 5kbumwy 98(jps. The car's average velocity during deceleration was 3 9(ymjwpb5k8u3 km/h. What was the car's deceleration while slowing down?

  An airplane increases its speed from 100 m/s to 160 m/ lw2o wn:q,h8j3i8pots, at the average rate of 8 38jp :iwnh2olwoq,t$15 \; m/s^2$. How much time does it take for the complete increase in speed?

  A car traveling 60 km/h accelerates at t y 4)s*maa:7sf2m 7aitcn)7kcxo g8kfhe 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 accel m.6zl(umv/vbfy22+ 5i bamzferates 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 constantez6gem984 grbj3pk 3/g e x2op acceleration jprgpbzg/e m3g8o 2 9ee46 kx3of $2.0 \; m/s^2$ for 15 s. At the end of this time, what is its velocity?

  A cart with an initial velocity of 6.6 m/s experiences a echpmk, tkk8,fg ; (e8constant acceleration of kk,8km,p8g(ece th;f$1.2 \; m/s^2$. What is the cart's displacement during the first 5.0 s of its motion?

  A bullet moving horizontally to the right (+x directio35ywy7wr6b0jc r8 kkyn) with a speed of 339 m/s strikes a sandbag and penetrates a distance of 35.26 cm. What is the average acceleration, iw kc687y5j0ywyrb 3kr n $m/s^2$, of the bullet?

  A jet fighter plane is launched from a catapult on an aircr tu2/chl dlt;5aft carrier. It reaches a speed of 42 m/s at the end of the catapult, and this requires 2.0 s. Assuming the acceleration is constant, what is the lengthl;t 5h2l t/ucd of the catapult?

  A car starting from rest moves with ek**.mm4so,lflu *wpdv jm, 0 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 in a distancr 1)qbam2v o4djns1)ee of 200 m. What is its average acq))r1os4 vj1e2 admbnceleration?

  An object starts from rest and undergoes uniform acceleration. During the firsb( lra rhg dfz7od2z.x)1+lu+t second it travels 4.9 m. How far will it tduo2f) (hx.ll g1rz+a dz+br 7ravel during the third second?

  An object is moving in a straight line with constant accelerat *s . uv0b)d/iwykfdj/ion. Initially it is traveling at 16 m/s. Three seconds later it is traveling at 10 m/s. How far does it move during this jwiy d0)d /sb/.*vkuf time?

  A car starts from rest and accelerisb s)wjzl5:pk: n p6:ates 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 dr-lp1yh:uy r90t 0/i kyr0sm uhy 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 traf)5bj0/i cjlejtq s;a3 fic light turns green, a car that has been waiting at the intersection starts ahead with a constant accelera;siqtejba)j0/3j 5 cl tion 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 planm,b r isipbw .j+: v)ke7;co,s*fh*suet X wherec, bhr*sk7.+esi:,j*vmsf u;oiw b p) the 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 speed of 12 m/s on the surface of 1cuhh(ys/+ ee -7ymfl*yd 1e vplanet X whe(7hhvyed1m yfe*l u1sy e+ /-cre the 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/sn n.yzbbyn+42rsb g9 p nu- d+uf0m1q7 on the surface of planet X where the acce g b-4s q9zdn2fyun n+r7y+. n1pb0mbuleration 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 wh vh/:qzdu8po1sm.hx3 5y4 qikere4qksm3dyio hv51 .u/:h pzqx8 the 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 than 0.10 s. If your friend hol1n f: *hyzli*3w ghz8tds a ruler between your fingers and releases it without warning, how far can you e 8tgl1:zin* hz*3hfwy xpect the ruler to fall before you catch it?

  A ball is thrown upward at a velocity of 19.6 m/s. Whabfzjt t 0t(t:1jz i*7zt is its velocity after 3.00 s?7ftt (j0zztzjt:1*ib

  A bullet shot straight q*z 6(iljcgt2 up returns to its starting point in 6 s. What is the initial speed of the bu l*i 6q(gj2tzcllet?

  A ball is thrown straight up with a speed of 36.0 m/s. Hvyur)t14 * zfyow long does it take to return to i)vuf1yz*rt4 yts starting point?

  A ball is thrown downward from the top of a building with an initial speed of 8 fro(j.l1) fvvm/s. It strikes the ground after 3.r.jf l)of(vv1 5 s. How high is the building?

  A ball is thrown straight up with a speed of 30 m/s. (only fill i uynoi9s:w y(a.2weaf gt 1 md.;ixgye7 :1sm,n numerical value in;,:91wniidyyt:71g m..ygx 2efe(a wss auom the 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 w7zz/ lfuq :uo+m/bo)z8+b qt)8sl/v m3d hwgzith a speed of 37.4 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 12 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 12.0 m above the point of contact a second time.  (数值)  $s$

  In Fig. below, what is s.zw+p;k elcnsj+82l the velocity at t = 1.0 s?

  In Fig. below, what kjwxwy/ns ; jn)1c- drewu:-lx*1o.tis the velocity at t = 2.5 s?

  In Fig. below, what is the velocity at t = 4.ais -u:plu k2d,p1zv (0 s?

  In Fig. below, what is the velocity at t = 5.5s x pjs b1():3sz2xpgp s?

  In Fig. below, what is the udl 79kvo0j3maverage velocity from 0 to 4.0 s?

  In Fig. below, what is the average velocity from 0 to .)oo m::pq.tvv:egp6s g )jja6.0 s?

  In Fig. below, what is the accela0n14pb jz0 mleration at 1.0 s?

  In Fig. below, what is8rp*if9n 1j xc/tvt,d the acceleration at 3.0 s?

  In Fig. below, what is thepc(4p )vjo* l5z40s zon2qdbn average acceleration from 0 to 5.0 s?

  In Fig. below, what is the a 80k.uhuo w xc-(ed,u xxly/b* ac0fc/0fag8bverage acceleration from 0 to 8.0 s?

  In Fig. below, what is the displacement from 0;dwqe(g v.*6-wvkwbw to 8.0 s?

Does a car speedometer measure ocyme+ cx j,u;2 jha;5speed, velocity? {speed|velocity}

  An object can have a varying speed if its velocity is constant.34)dbt0etr1 xsgsrc 2 p kb+a:

  The velocity of an object can be negative when ii65cxj3hrc 3vtt 71hnts acceleration is positive.

  If one object has a greater speed bj.cbxn;l5a 5 than a second object, the first must have a great5;a xb lnc5b.jer acceleration.

  Two cars emerge side by side from a tunnel. Cauzax/m- zov+6vs( tof lu44y.r 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 as its acceleration decrea1n h 8vs/yj*kh;ydulnp 0 7:kfses.

  A baseball player hits a foul ball sttapt +zxsosdrx9c zk(f :+7.- raight up into the air. It leaves the bat witzfs a+xk9-tc+.ozr7 tdx:p(s h 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 hajt ;- 9sel)i84kvlnmyppening to its acceleration, how does it changel4 ik9njl t;me8-vy )s if air friction is ignored?

  As a freely falling object speeds up, what is happening tok s;j ,9*nzy4/9s ztbxhl+imi its acceleration, how does it change if air hmj+;4, 9ibxlt/sy9zzis n k *friction CAN NOT be ignored?

  An object that is thrown vertically upward will return to;(qlav d.rr 9c its original position with the same speed as it had initially if air resi;cd. r(rla q9vstance is negligible. If air resistance is appreciable, how will this result be altered?

  An object can have zero velocity and nonzero acceleration at the same timbhferjx16p7w ;w3z5w o idn *2p7ork* cq,bw 4e.

  An object can have nonzero velocity and zero accelerationio +q/ qxx-4tb at the same time.

  An elevator moving from the second floor to thydk/ nci:zy+ (e fifth floor making no stops along the way has zero acceleration all thek( :z/nyyi+ cd time.

  A rolling ball moves frojdo /2gzlmwo i8)q sqk)/2/anm $x_1=2.4 \mathrm{~cm}$ to $x_2=-7.0 \mathrm{~cm}$ during the time from $t_1=2.1 \mathrm{~s}$ to $t_2=5.4 \mathrm{~s}$. What is its average velocity?  (数值)  $cm/s$ (only fill in numerical value please)

  A particle at $t_1=-2.7 \mathrm{~s}$ is at $x_1=2.7 \mathrm{~cm}$ and at $t_2=3.5 \mathrm{~s}$ is at $x_2=8.0 \mathrm{~cm}$. What is its average velocity?  (数值)  $cm/s$

  A person jogs eight complete laps around a quarter-m* ( btvbu1q acilqh-/9h utq9 1,jd1wbile ($1 \; mile = 1609 \; m$) track in a total time of 9.3 min. Calculate (a) the average speed  (数值)  $m/s$ and (b) the average velocity    $m/s$

  A horse canters away from its 9.-a 2kmj8kwyl ur4 t.uglv sf3kc1x:trainer in a straight line, moving 114 m away in 12.6 s. It then turns abruptly and gallops halfway back in 4.7 s. Calculate (a) its average spl2-.u8ks1gut9mrkf4jyx : 3 cvk.lwaeed  (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 fr 4wg jl4v-559vjntv;m3ovg ocom $12 \; m/s$ to $23 \; m/s$ in 5.8 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 froo txs(gvyrmu,0.cn 1m+ y*r4hm $16 \; m/s$ to rest in a distance of 69 m. What was its acceleration, assumed constant?  (数值)  $m/s^2$

  A light plane must reach a sp * zw4hi 1x,zokbp+8 t(z1 gjydje0xx.eed of $29 \; m/s$ 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 burst out of the blocewd 6qnbaj ,ua1 b+5;vks to essentially top speed about abbe5n ;a16q+w jv,ud$10.9 \; m/s$ 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 uniformly frms/yc3-y t1vf 3hm(bv om a speed of $17 \; m/s$ to rest in 5.70 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 highwa; eae.d4dtn/4wf)4zc kjz, hly. Assuming a def d4hezaw;t) dc ez,4/.nkl4jceleration of $7.00 \; m/s^2$, estimate the speed of the car just before braking.    $m/s$

  A car is behind a truck goino+bs2w ,m5 frdg $25 \; m/s$ 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).    $m$