Suppose that an object travels from onm rz+z d/5vf9ye point in space to another. Make a comparison between the displacement anv z5f9dym+ /zrd the distance traveled.

  When is the average velocity of an object equal to the instantaneous veloc.cooa*)iir na de-+w2ity?

  A new car manufacturer advertises that their car can go "from zero to rbr)+ 5.zp(luwx6 0d9v9 ccey ogvg3w v k,6ndsixty in 8 s". This is a descriptzvkp v6+ccoduw9b ( 9rw yld5n,)gr 3.gv06x eion of

  An object moving in the +x axis experience oad i biuj7+4:08vebns 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 sv.9 ez(jq7hbq*z(cf9pi 3 at zlow down as it approaches a traffic light. Make a statement concervi z9zf*.( z ja37e 9tqqcpb(hning its acceleration.

  Suppose that a car traveling to the West (-x direction)b5c if8hkxd.t u.4rey*qa;p0 begins to slow down as it approaches a traffic light. Make a statement concerning its acceleratib0frp.;etahq * 5udx 8ycki.4on.

  Suppose that an object is moving :ti7;i *xvja tla 0ip*with a constant velocity. Make a statement concerning its iia* jta0lv:*7;pxti acceleration.

  If the velocity of an object is zero, does it mean that the accelera,:ej ijkdiw) mxrl20) tion is zero? Support )2 )xdrlm:ew,j 0ijkiyour answer with an example.

  Can an object's velocity change direction when its acceleration is con:1ftk;b9/m n ,yhmvssstant? Support your answer y/mv1sh :s;t b fm9n,kwith an example.

  Suppose that an object is moving with constant acceler/mkrg du.9r(n q9xsb7 ation. Make a statement concerning its motion with respect 9gxu9km.bnq7s (d/ rr to time.

  Can an object have inhay14 jt9)sh5zq,u31ptw2au phgr (mcreasing speed while its acceleration is decreasing? Support your ansgz1hmhu5 pj 9(u pt2s)qyarwta,h 341wer with an example.

  Suppose a can, aftertvx;0;o b f vr;/-bm3ktw8 icr an initial kick, moves up along a smooth hill of ice. Make a statement concernio b;xtm83b;/rr-fw c;tvi0kvng its acceleration.

  Under what condition is average velocity equal to the average of the object's eeh) v*v8c/edinivhd/e*ee8v)c tial and final velocity?

  Objects A and B both startjyx : 4)j8gya-,g8elyv. xkwh at rest. They both accelerate at the same rate. However, object A accelerat yy,k8jlwehgv 8xj4x:y-.a g) es 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 rest. They both accelerate at the same rativr 5/eco xs1q s/4(wze 4wl6dzd64y ne. How1 4 ss y czdv(diz/lq4oxw4n/ew66r5 eever, object 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 frbi m;j3 n7a)iuom rest and falls in the absence of friction, which of the following is tnu3; imji7)barue concerning its motion?

  When an object is released from rest and falls i od;a+nhe7t1tm+3 fcjftg h)6n the absence of friction, which of the following is true concerning o; +jtm)7htaht ffge 1cn6d+3its motion?

  Suppose a ball is thrown straight up. Make a statement about the velocitcqt :efj 8/ev aoiaqe3v:e2.+y and c fe8aeivt qa.23o:ejeq+v :/the acceleration when the ball reaches the highest point.

  Suppose a ball is thrown straight up. m mh.qb,n4w9 ylys) 0s5od7w kWhat is its acceleration just before it r )d.w7 ohsy9,sn k4wq y50mbmleaches its highest point?

  Suppose a ball is thrown straight up, reaches a maximum heightu4 dec+q 0hq 8uqb /j;;izloq9, then falls to its initial height. Make a statement about the direction of the velocity and accqu+hzq0ql;bu9ic q8/dj; 4e o eleration as the ball is going up.

  A ball is thrown straight up, reaches a maxi*h4, pishz6b ymum height, then falls to its initial heighhpy*i4z hb6s,t. Make a statement about the direction of the velocity and acceleration as the ball is coming down.

  Suppose a ball is thrown downward in the abs7 lj9j2iw2 w-alvckg 1ence of air resistance. Make a statement concerning its acceleration- lvw kj9wc7igj al221.

  Suppose a skydiver jumps from a high-flyoltf2/u9 se*j:l;o4zad bkxx 4xc. + hing plane. What is her acceleration when she she reaches terminal velocitabs/ ud9 2czo4xot; *xeh +x f4jll:.ky?

  A ball is thrown vertically upward with a speed v. An identical second ball iroag0ejeu2xe1t )c3ns h/7 d,s thrown upward with 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 seconneh) s a d1tjr30c,o2/exe ug7d ball go than the first ball?)

  Ball A is dropped from the top of a building. One se9fb,6l *k ubtkcond later, ball B is dropped from the same building. As time progressel,9fkkut*6bb s, the distance between them

  Ball A is dropped from the top of a building. One secon/.a596sn l 9bjra0 tihotl3jnd later, ball B is dropped from the same building. As time progresses, thotr/at. n5slb6930 jinjalh9e difference in their speeds

  Two objects are thrown from twjxepv7u a 0e*yb7q ,:ei,a -lsf18zon(.gsihe top of a tall building. One is thrown up, and the other is thrown down, both with the same initial speed. What are their speeds when tq,z0 o 7lgy8( :jub., 1vx*eaep7 si waisnfe-hey hit the street?

  A brick is dropped from the top of a building. A second brick is thrown stra w7 b8s,* ) ,tqnnvotutcy(zk2ight down from the same building. They are released at the same time. Neglect air resistance. Compare the nw ky,(8 uts, *tqzo72 n)ctbvaccelerations of the two bricks.

  An object is moving with constant non-zero velocity in the +x axis. The pogf(xpu k cj cdm48 f1ez)880mysition v8mg)z188fp ky jmuc 0dfxe4 (cersus time graph of this object is

  An object is moving with constant non-zero acceleration in the +x hl10pea 29zsi axis. The posit lpih0sza 219eion versus time graph of this object is

  An object is moving with constant non-zero velocity in the +x axis. The velocityd1 )z wr x3.ym:edqn-scf/k w, vzsf xr3w d/ dn.c- :q,m)w1eykersus time graph of this object is

  An object is moving with constant non-zero ac, sp8): cxsq5arog6ag,p6ns eceleration in the +x axis. The velocity versu xsa)g8n,6ap6oc: qsgr 5,pses time graph of this object is

  The slope of a position versus k5 n;r()kg lgrtime graph gives

  The slope of a velocity versus tizvahx( 4q3rc2thzo koc6z 65; y3fw j2me graph gives

  The area under a curve in an accel0o + j-cl+jskll+t jvcs(2p)aeration versus time graph gives

  The area under a curve in a velocity versus time .6ic+ 6yi5yv mmr2vlbgraph gives

  If the position versus time grapyk*w,(/oir* y( zqg: qd(a et4ki5jkxh of an object is a horizontal line, the object 4o *5,grad:xj (k(/qky iyteqkiwz* (is

  If the position versus time graph of an object is a vertical line, the obalm7-mc5ezjr 4 )k 6uuject israecmjk5 7)m 6uzu4-l

  If the velocity versus time gra6w6p 4dz d,ptfph of an object is a horizontal line, the object 6pp ,fd4t dw6zis

  If the velocity versus time graph of an object is a straight line making an an gnb4nkb-:6ckgle of 30 degrees with the time axis, thecbn: n6b-g4 kk object is

  An object moves 15.0 m north and then 11.0 m south.1u8p8g yz b6pi Find both the distance traveled and the magnitude of the displacement vector.8p86 1yi zpbgu

  A boat can move at 30 km/h in still water. How lo;qdbit6w 9tp r.mmx4;ac:w:x ax:)qvz/ x /hkng will it take to move 12 km upstream in a river flowing 6.0 km/:qwmxa:4xbk/ cv ;haqm9x) ti rw./:p;xt 6 dzh?

  55 mi/h is how many m/s? (1 mip88( yv slh)bk = 1609 m)

  What must be your aver j-uu-rkt 9+ov0dr ,bnage speed in order to travel 350 km in 5.15 h?

  A runner ran the marathon (approximately 42.0 km) in 2 hours and 57 min. W(i,s ys,kor)2o3 w+ayt l- cpkhat is the average sperysl iopyk(3 ) kct-2wa+, so,ed of the runner in m/s?

  A car travels 90 km/h. How long does it take for it tdr:uo7w +h9yc31tkhn o travel 400 km?

  A ly (light year) is the jasl3w257avb distance that light travels in one year. The speed of l2slw ja7 va5b3ight 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 look t9-ff +j+ /s0ju ck/jsfwik cj:o the side for 4.0 s, how far do you travel during this inattentive period:iu cwfk c++s9/jf0/-j jskj f?

  If you run a complete loop around an outdoor track 1(hqoij;3d/ vsr7iym ;oebf,(400 m), in 100 s, your average veloc m,o/ 71iis;; j3rvy(hdq oefbity is

  A polar bear starts at the North Pole. It travels 1.0 km so/ ptvi-+ jx,i+8yx ezfuth, then 1.0 km east, thenez ,+txjy+ / pivx8i-f 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 at the Nort::57kr7 bfal3 angww ,ibhs,k h 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 starting point. This trip takerkn wkb wglaa,::7 3fbihs57,s 45 min. What was the bear's average velocity?

  You are driving home onc i,4,dqr q2mnt8h2 n2irn ct; a weekend from 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 is your hometown fro2i 4r;8d2 c rtn2qqi,cht ,mnnm school?

  A motorist travels 160 km at 80 km/h and 160 km at 100 km/h. 6nrl u-tl a/d9l(qb5m What is the average speed of the motorist for this trip?lm 6d5 9bt(r/nu-ql al

  A motorist travels for 3.0 h at 80 km/h and 2.0 h at 100 km/h. Wpx/, sng zzqe2pjv. qsi/u t .j8*stuv/qy -35hat is her average speedjtt,veqg*v823nup-s/ y/ q isupj s..5/qzx z for the trip?

  An airplane travels p 44pi58sh 1qvdtqn sv):x87x 1vp cdrat 300 mi/h south for 2.00 h and then at 250 mi/h north for 750s:vpi8qxvp1vt5h 44d spcx1r n) dq78 miles. What is the average speed for the trip?

  In a 400-m relay race the anchorman (the pmm;5tfo* sl-,7ofk zix m0d 1serson 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.zx0f kls*-miom,t1 ;o s75fm d1 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 13 s. The car's averac1d.n* 0/qghmzkg .k3xqy k- dge velocity during deceleration was 30 km/h. What was the car's deceleration wdxk qq*g-khm0nd/3yk.. gz1 c hile slowing down?

  An airplane increases its speed from 100 m/s to 16h .tfw 3 qq+lugfq q*7-f.f8cr0 m/s, at the average rate of +c.gq 8f- 7fqqf *l.hrqwu f3t$15 \; m/s^2$. How much time does it take for the complete increase in speed?

  A car traveling 60 km/h accelerates atb 5ohwi e /a+dig x0p;2w /;umjs4gtg9 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 acceleraq8tg-9yk( vcites 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 t,w(rb;o 5ic)y nl:ekxhen speeds up with a constant acceleratio:),(lx i5w nobre kcy;n of $2.0 \; m/s^2$ for 15 s. At the end of this time, what is its velocity?

  A cart with an initial velociqj0*gv2z 9 zl detw l5q-ra56zjmph20ty of 5.4 m/s experiences a constant acceleration of590z a 2gl q-6mz5pq0d*wle2hrj jzvt $3.0 \; m/s^2$. What is the cart's displacement during the first 4.2 s of its motion?

  A bullet moving horizontally to the right (+x direction) withcq c 6qm1n*gz9d(hfz / a speed of 252 m/s stri/z1hn6gmf qdc z(9 q*ckes a sandbag and penetrates a distance of 22.95 cm. What is the average acceleration, in $m/s^2$, of the bullet?

  A jet fighter plane is launche(l+vx7hspgxb13n(a i d from a catapult on an aircraft carrier. It reaches a speed of 42 m/s at the end of the ca3a(+lbni hsg 7v1 px(xtapult, 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 constyo6t,js r /ot8t( k /qsg4pl3tant 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 distance of 200 m. What is its av:nm 4ty4k3 ji oy1yqf(erage acceleyqfo3 :mjy 1nk44ty (iration?

  An object starts from resy *ikkuo la(w*,nol30t and undergoes uniform acceleration. During the first second it traveolkuk* n 3*il,y aw(o0ls 6.9 m. How far will it travel during the third second?

  An object is moving in a straight line with constant acceleratiokk bq(9r0syr o 87ie(sn. Initially it is traveling at 16 m/syo0 q8eks(b rk7irs9(. Three seconds later it is traveling at 10 m/s. How far does it move during this time?

  A car starts from rest and accele,8ifc3 vbo1sw:qlh; a rates 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 dryb 4swh:-d gg hj26ei1y 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 l srppob.u 4tu1;wo61 zubgj03 ight turns green, a car that has been waiting at the intersection s3o;0j6r1s ob gpubpw4t.z1 uutarts 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 upward with a speed of 12 m/s on the glg niuq847 3mwsu 9p9surface of planet X where the accelu9uil34spmggqn 7 9w8 eration 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 planet X whj2z7bk 5- snrqere the accele7 srk2qjn zb-5ration 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 upwz.oxz jhk+/95mj mq-pard with a speed of 15 m/s on the surface of planet X where th j-9z.qopkm5z/ hx+mje acceleration 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 orw.r8j vc5m y a6/,svzf 14 m/s on the surface of planet X where the y8 r,mzv6s.rac5w j/v 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 usual0z578; :x5mxxsl amw0ppwcnaly greater than 0.10 s. If your friend holds a ruler between your fingers and releases it without warning, how far can you expect the ruwxxm;7:m0x a azn0 cppl585 wsler to fall before you catch it?

  A ball is thrown upward at a velocity of 19.6 m/s. What is its vel 5l ;ebjd7y4pz bnf3)wocity after 3.00 sfb 3d7 ly5e4bn wzp;j)?

  A bullet shot straight up returns to aaxh p49z/bsn4t i f-ti,v 0s4its starting point in 12 s. What is the initial speed of the b-inxi04bpv4az9f , tha4ss/t ullet?

  A ball is thrown straight up with a spee/9iuoixrp7 y8d of 36.0 m/s. How long does it take to return x8ipyui/97or to its starting point?

  A ball is thrown downward from,ozk 6x5w -dhz;qmis7 the top of a building with an initial speed of 14 m/s. It strikes the ground af oimz,x sz;hw5dk67-qter 2.8 s. How high is the building?

  A ball is thrown straight up with a speed of 30 m/s. (only fill nvv fk )q l9-tk:,x8jkab o.x5in numerical value in the bl xf,t8.kqx-:)aok kbv vn9 lj5anks)
(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 zffvus- t)x s4l,yo /2with a speed of 30.1 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 14 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 14.0 m above the point of contact a second time.  (数值)  $s$

  In Fig. below, what is t q3q)yn (+/jjerpzel* he velocity at t = 1.0 s?

  In Fig. below, what is the velocibrr9 zl:2 3vc *tr1spqty at t = 2.5 s?

  In Fig. below, what is)idv dqrn:5d j,ox-q* the velocity at t = 4.0 s?

  In Fig. below, what isw,.n*, tfij;o uq y1cz the velocity at t = 5.5 s?

  In Fig. below, what is the average veloci a1xb k2 2s3ingumj3 (ji+rkw;ty from 0 to 4.0 s?

  In Fig. below, what is the average velocity ftm0,. nn8m mdee4p( dnrom 0 to 6.0 s?

  In Fig. below, what is the acceleration atwsk,au3u; qc. 1.0 s?

  In Fig. below, what is theg-5+ro .apu rh acceleration at 3.0 s?

  In Fig. below, what is the anfwc6* ezv8h /verage acceleration from 0 to 5.0 s?

  In Fig. below, what is the 4h khcm ;-ifh-.+x0d vxn(n )dxk:ft0 v*qnmh average acceleration from 0 to 8.0 s?

  In Fig. below, what is the dispu psv; 12h yw(vena6h)zn6hz 3lacement from 0 to 8.0 s?

Does a car speedometer measure speed, velocity?m+ .) xzny3xbmsruk-pqc(p1 5 {speed|velocity}

  An object can have a varying speedt- c*tpz8f a)*9lufgzt kw )3m if its velocity is constant.

  The velocity of an object can be negativew+ jtgyyg h,q9g:zn 6(wjjd -8 when its acceleration is positive.

  If one object has a greate5b6)sc0o 2cr 8i vfyjnr speed than a second object, the first must have a grej8bv5c2o sif yrn c0)6ater acceleration.

  Two cars emerge side by side from a tunnel. e ujvoh 3lx)bgb.aw6 7at2z-5Car 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 2sc xun*spn d:bl9t7u2h 5 3cmdecreases.

  A baseball player hits a foulb( q e;dc4*wqc ball straight up into the air. It leaves the bat wd q(wcq;eb4* cith 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 s8/zfq;mjsq 781exo)m . p6hqsh swgh 4*7l zzcpeeds up, what is happening to its acceleration, how does it change if air friction is s f).zc6*ez sm wqhqmh8plsoz;j7qxh7 8 /41gignored?

  As a freely falling object speeds up, what is happening to ityaq48)fh 1 u31j* kcciz8okmq s acceleration, how does it change if air ff4k 8)qkoc*1jai3 muyq81zhcriction CAN NOT be ignored?

  An object that is thrvs d 7-cl tcfzu4;1h3uown vertically upward will return to its original position with the dcu1c 47z sth3 vl-u;fsame speed 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 x t1(drd8d pqavnh 5 3th1kd 3xif1l+,velocity and nonzero acceleration at the same time.

  An object can have nonzer u4qjveiq5g -5o5acr- o velocity and zero acceleration at the same time.

  An elevator moving from the second floor to the fifth flof71 fav, sld-tgr pp5;or making no stops along the waa p7 l1f t,sfg5dvr-;py has zero acceleration all the time.

  A rolling ball moves frsm /f/:hdyg u 1,btc+hom $x_1=2.8 \mathrm{~cm}$ to $x_2=-8.0 \mathrm{~cm}$ during the time from $t_1=0.9 \mathrm{~s}$ to $t_2=5.2 \mathrm{~s}$. What is its average velocity?  (数值)  $cm/s$ (only fill in numerical value please)

  A particle at $t_1=-4.3 \mathrm{~s}$ is at $x_1=2.3 \mathrm{~cm}$ and at $t_2=3.9 \mathrm{~s}$ is at $x_2=7.3 \mathrm{~cm}$. What is its average velocity?  (数值)  $cm/s$

  A person jogs eight complete h(hb -jo9q,bdlaps around a quarter-mile ($1 \; mile = 1609 \; m$) track in a total time of 6.8 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 xbv*ke /eetetx5s90)3h5 psck6 iq1;wiqmz0straight line, moving 92 m away in 10.2 s. It then turns abruptly and /xkt0sc0ti 9q pw se ekbhime5z 51x* )qe63;vgallops 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 from5jfqii/h+( km $12 \; m/s$ to $22 \; m/s$ in 4.3 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 .7r c5c vuv0hi$22 \; m/s$ to rest in a distance of 84 m. What was its acceleration, assumed constant?  (数值)  $m/s^2$

  A light plane must reach al,r2e5j .2a u)4(o2 hhfomclf vu v:yz speed of $28 \; m/s$ 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 gzxx) b .np-w)b pa/b3kjrew*pnh 9/5out of the blocks to essentially top speed about )bg/xn ) b*. beka-pw jwx z53/ph9pnr$10.7 \; m/s$ in the first 14.7 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 aylw3p-y g.ujkch3ek-i x/8-g speed of $18 \; m/s$ to rest in 4.20 s. How far did it travel in that time?  (数值)  $m$

  In coming to a stop, a car 3mlgftqb-o- vd2j-, wleaves skid marks 92 m long on the highway. Assuming a decelera-bw g3-qd ot-,fvmj2ltion of $7.00 \; m/s^2$, estimate the speed of the car just before braking.    $m/s$

  A car is behind a tr(5,w z*pmzqfm uck 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).    $m$

  A runner hopes to complete the 10,000-m run in less than 30.0 min. Aftlshcpdtn-i*,dk y9 :0 er exactly 27.0 min, there are still ikpc9 *ysn ,hd0-d l:t1100 m to go. The runner must then accelerate at $0.20 \; m/s^2$ for how many seconds in order to achieve the desired time?    $s$