Suppose that an object travels from one point in space to another. Make a comszi )leek/tds t2h(m*i 95to4 parison between the disme etd*)9isitk( 2/t5hs 4o zlplacement and the distance traveled.

  When is the average velocity of an oboeenvqjzns/62zz67l .( rn 8-or wfl :ject equal to the instantaneous velocity?

  A new car manufacturer advertises that their car can go "from zero toi)bbzdx w+-i+(n yxm / sixty in 8 s". This is a de /wm)dz b+nx bi-+(iyxscription of

  An object moving in t h8 9jbkk8fmqxn;vl.1qt; x2l 4g zsu:he +x axis experiences an acceleration of $2.0 \; m/s^2$. This means the object is

  Suppose that a car traveling to the East (+x direction) begins tocy.v (m7lgxcr7ge( *us1aljh6 ot .+f slow down as it approaches a traffic light. Make a statement concerning its accele*. 1(s6+jov t c ameycglugxh7r f7l.(ration.

  Suppose that a car traveling ts;w1 ts0a.nbw1 kg4w bo the West (-x direction) begins to slow down as it approaches a traffic light. Make a statement concerning w0114bw. bswgs;k a tnits acceleration.

  Suppose that an object is moving with a colivon*w ; e86cnstant velocity. Make a statement concer;*o il6ew8 cnvning its acceleration.

  If the velocity of an object is zero, does it y:xxdmhl5 4 dwh;lh7: mean that the acceleration is zero? Support your answer with an xyxh lmhl:w d45 :;7dhexample.

  Can an object's velocity ga 2enr4(sr h9 +jn4fqchange direction when its acceleration is constant? Support your answer with an exam2f rq4jn( s94rea+hng ple.

  Suppose that an object is moving with constant acceleration. Ma):2t r-d,bv6x, ivk ylfu r 08wz10feg4 csbrske a statement concerning it cw gbv 8zu y2f 4tr )is1r0bxvs-r6,:0,efdkls motion with respect to time.

  Can an object have increasing speed while its ozsnw3* .hx u8rc/g6- skh; i 37h/mwer al4ydacceleration is decreasing? Support your answer with ag7rwzn 3do i*l.4h ;e8cr-yk xss6/h/muh3w an example.

  Suppose a can, after an initial kick, moves up along a smooth hill of icee392bg2p1 bfap d51q t7pjtoc. Make a statement concerning its acpd9 2a1pbt f7o 2tceq j5pg31bceleration.

  Under what condition is average velocity equal to the average of the objecf* 0moez(3 na futek/5t's initial and final*a5 eomfe/ tfn3zk(0u velocity?

  Objects A and B both start at rest. Th1jv* g7qeb; a(afoy;qnhu7n k0d,2 se ey both accelerate at the same rate. However, object A accelerates forb;u,n qj; g*72n(aof0ke1yeq d avh7s 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. sq.f o1n.mk q- haldr7 0y-df: They both accelerate at the same rate. However, object A accelerates for twice the time as ob-1ddrl qfkm0ofh.ya7- :q n.sject 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 f va*qn.t nlwef 9h+),sriction, which of the followi snl .feawn+,t)*vq 9hng is true concerning its motion?

  When an object is released from retdx (5zkj-hx* v*j.nxst and falls in the absence of friction, which of the following is true con(-*t.vj kjz5xd xh*xncerning its motion?

  Suppose a ball is thrown straight up. Make a statel+)/t uqnq ym6j-g p,0d xrv)zment about the velocity and the acceleration when the ball l mx ),dnqu j/p+vtz6y gqr)-0reaches the highest point.

  Suppose a ball is thrown strawxa z*/3ssq4rw/nu, iight up. What is its acceleration just before it reaches its *xr w3sq / zui/4,wanshighest point?

  Suppose a ball is thrown straight up, reaches a m qcqlyzl60; ohbx6,y78u.g6 k( sblluaximum height, then falls to its initial height. Make a statement about the direction of the velocity alchzsl.0l7l;ub(6ux gk 66 byo ,q 8qynd acceleration as the ball is going up.

  A ball is thrown straight up, reaches a maximum height, then falls to its init y3j-g1 cog.v xd )zqzi(xfzn-y2u 6l2ial height. Make a statement about the direction of the velocity and acceleration as t fjy2x(zggxi6uy3z 1olc-zv ).q 2 -ndhe ball is coming down.

  Suppose a ball is thrown downward in the abs4m ua diqi*v1;sozo-s9-mv 0cr2 *ym qence of air resistance. Make a statement concerning it-ov0*sv ids4; moq-qm* 1a2iyz9rcums acceleration.

  Suppose a skydiver jumps from a high-flyingmgcrsd* j 11ure+1p7dd 9i l xxsi70.a plane. What is her acceleration when she she s9rmdc0d7.p*lxrj1xu1s g iide a17 + reaches terminal velocity?

  A ball is thrown vertically upward with a speed v. An identicalwivu 3f(p 8+:zlexw i0 second ball is thrown upward with a speed 2v (twice as fast). What is the ratio zwiu308wv:i(l xfep+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. One se/blca 1x)edq* + 1f.m;rvyvz-f t f2bdcond later, ball B is dropped from the same building. As time progresses, the distan vb 12x -dft/1mbf*;qdc+a zv.rley)fce between them

  Ball A is dropped from the top of a building. One second later, ball B is dropsgwwygc 4l- nd7 tqr pzd4601/djth74ped from the same building. As time progresses, the difference41cwslqh6z gd/ 7t wtrd4yndg4 0jp-7 in their speeds

  Two objects are thrown from the t ;eul s ;:jje;nywih4/op of a tall building. One is thrown up, and the other is thrown down, both with the same initial speed. What are tejlije;nys4 ;:hu/ w; heir speeds when they hit the street?

  A brick is dropped from the top of;hw(6 f rxnmu vja6i1; a building. A second brick is thrown straight down from the same building. They are released at the sr6nm ( f;uwji6ahx; 1vame time. Neglect air resistance. Compare the accelerations of the two bricks.

  An object is moving with constant)5mb6/uhx0o0b rme( - eonatc non-zero velocity in the +x axis. The position ve/oh be6 u(ot)be -anmrc500mx rsus time graph of this object is

  An object is moving with constant n4cehg1qq8s -non-zero acceleration in the +x axis. The position versus time graph of4 q8qg1-h cnse this object is

  An object is moving with kiw;5r3uj xb0constant non-zero velocity in the +x axis. The velocity versus time graph of this obk5jr;0 bx 3iwuject is

  An object is moving with constant non-zero accele51ot9 u-x*g7 tme vnlxration in the +x axis. The veloo*mxtxn9 7 1v-lut5eg city versus time graph of this object is

  The slope of a position versus time graph givesagx1 4g18;:j4hwrkdg:h zjww

  The slope of a velocity versus 02mih i56efb vtime graph gives

  The area under a curve in an ac/og2 ylad a)ha4 o6.p;5lo7ajghts)a celeration versus time graph gives

  The area under a curve in a velocity versus time graphm7 89vyrz v0+mpcd buw 58 )gzhy3(bgq gives

  If the position versus time graph of an object is a horizontal line, the obys199ml;z 7h ujbv 7qzject bms7u vzy197qh9 zl;jis

  If the position versus time graph of an object is a ve3rr.x (eua8tcrtical line, the object is3 rae.ctx8 r(u

  If the velocity versus vak ) tb 4b: n9.e3t,xegpzlv+tjo;p+time graph of an object is a horizontal line, the object is.zx evo+;jtg b a p4tklvb9: t3+)nep,

  If the velocity versus time graph ofrahn3 dtz: ,s,/rep*uvgml 5o*u 3gi3 an object is a straight line making an angl/3 z3vhdto, ra p*uglur3n *e5g:mi,se of 30 degrees with the time axis, the object is

  An object moves 15.0 m north and thq, w 7snqo/i7sen 11.0 m south. Find both the distance traveled and t7q i,qswon 7/she magnitude of the displacement vector.

  A boat can move at 30 km/h in still water. How long will hd-h*.jx7n ;ju pjww3 it take to move 12 km upstream in a rivedwwj*7 ju hj.3p n;xh-r flowing 6.0 km/h?

  55 mi/h is how many m/s? ( /x*9uzfauw um kxmjg b69;hmy)4p)5g1 mi = 1609 m)

  What must be your average spi a9ul0-..v q9nyq(1mcosupglzp4 / q eed in order to travel 350 km in 5.15 h?

  A runner ran the marathon (approximately 42.0 km) in 2 hours and 572e:s b dn)om3q min. What is the avermeo 2s :qbdn3)age speed of the runner in m/s?

  A car travels 90 km/h. How long does it take 0r 6q mzl7mi6.ywiut7for it to travel 400 km?

  A ly (light year) is the distance that z9kirx.itip-yr0l yxt/; / w*h: e.lcv +j2tflight travels in one year. The speed of light iyx*tt:. f2;lkwlv/rc.zi ij y i+-/ xeph9rt0s $3.00 \times 10^8 \; m/s$. 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 852kq42fs e iqy1o gqbkypie;a+/h,sand you look to the side for 4.0 s, how far do you travel during tie;ae2 yfsq1+ 8qksk ,o5/4gby2iq h phis inattentive period?

  If you run a complete loop around an outdfuouw7g*l-26zc9ey- h 7enrdoor track (400 m), in 100 s, your average veloci u-nu2yc97eoe7l*z6whrgdf-ty is

  A polar bear starts at the North Pole. It travm7)eoeslxxi;pk4( o1els 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 takes 45 min. What was ksx1m x)oelp ;74i (oethe bear's average speed?

  A polar bear starts a.ey770yzuy,g h u0pzot the North Pole. It travels 1.0 km south, then 1.0 km east, thuyep g .00zz7,u oyh7yen 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 velocity?

  You are driving home on a weekend from school at 55 mib:qu3 gb-y1 - .eg) qcrm0p8pn)wds ni/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 farg)3):nrgsp mq-i.u 8yqb0c-1dpn wbe is your hometown from school?

  A motorist travels 160 km atfc0q)py obhl*0qbym4) l , 6tw 80 km/h and 160 km at 100 km/h. What is the average speeq0l)fyhcly)b btqp4 ,60m w*od of the motorist for this trip?

  A motorist travels for 3.0 h at 80 km/h and 2.0 h at 100 km/h. What is h a ya26)roz7fuo p8v4ser average speed for thea6ys8)4r z2 7aou opfv trip?

  An airplane travels at 300 mi/h south for 2.00 h anqtb+0qg4e xc u 5a7gw+d then at 250 mi/h north for 750 miles. cg0+qxe gu5baw7q+4t What is the average speed for the trip?

  In a 400-m relay race the anchorman (the person who runs the last 100 m)6o)hx0.eg fxe-:ar37kkibzq for team A can run 100 m in 9.8 s. His rival, the anchorman for tezq )f3:k7aegr6-bkx. x 0eiho am 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. 2uqxlyx :)2vj The car's average velocity during deceleration was 52xv qx:lyj2u)7 km/h. What was the car's deceleration while slowing down?

  An airplane increases its s6 yci/v;5a/n ncv:e:yd y5px tpeed from 100 m/s to 160 m/s, at the average rate of :/i/n 5y a vt5;6v: yxcpeycnd$15 \; m/s^2$. How much time does it take for the complete increase in speed?

  A car traveling 60 km/h accelerates at the rate j -1ey:jtq 4xcof $2.0 \; m/s^2$. How much time is required for the car to reach a speed of 90 km/h?

  A cart starts from rest and accelerates asc3 ;*xa1uly 7wc. huct $4.0 \; m/s^2$ 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 h s4t6wzyqf81s. It then speeds up with a constant acceleration oz h4 yf186wsqtf $2.0 \; m/s^2$ for 15 s. At the end of this time, what is its velocity?

  A cart with an initial velocity of 8.0 m/s experiences a consta.9 p 4amllk) g)zlxc;snt acceleration of ;)g.k 94c)plllx zsma $3.7 \; m/s^2$. What is the cart's displacement during the first 4.6 s of its motion?

  A bullet moving horizontally to the right (+x direction) with afvx1r5qb l*f0 speed of 448 m/s strikes q1f x5*0bfrvla sandbag and penetrates a distance of 39.93 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. eln n5 8q5jg1l It reaches a speed of 42 m/s at the end of the catapult, and this requires 2.0 s. qnln58j51 el gAssuming the acceleration is constant, what is the length of the catapult?

  A car starting from rest moves with constant acceleratd e,)puo2b( xaion 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. Wh/qyf4x)nh i 3cq+ (zr/vzq3qiat is its average accelerat zyir4q) f(3nvc+3ziq/x h/qqion?

  An object starts from rest and undergoes uniform acceleration. Dua3ii n2jld)8i c*bv(+oha; nv ring the first second it ilc2i)8d(oa;*n 3 vjn iv+bhatravels 3.7 m. How far will it travel during the third second?

  An object is moving in a straight line with constan g gz4*dzzeod1z .ydlyw 0f, 1*/ijhj1t acceleration. Initially it is traveling at 16 m/s. Three seconds later it is traveling at 10 m/s. How far does it move durijdli4ed,y zh./y*1 0 j* zwg1 dzgz1ofng this time?

  A car starts from rest and accelerateaa) thxp0m0h;s 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 tirelzb1 xhh3 k34* sb*:tjyz nu:xs on a dry 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 lighrst lne akh(y (/a4lzgcm2h39 3-7lx kt turns green, a car that has been waiting at the intersection starts ahead 3rgz9ahkna 4 -ml2 lykt(/hxlse(c73with 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 mz elwmu9ibg3z;j , +h 3pcap7(/s on the surface of planet X where the cph( 3i3,megz+a ljw; zu97bp 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 1t;j(,2mcst po;e7mob2 m/s on the surface of planet X where the acceleration due to gravitypm; c7ot2;e j,bot(sm 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 ot jl z avw(5 r0lrt2n4x9gl,a/f 15 m/s on the surface of planet X where the acce2/9ltv ltr5zrgawlnxj( a ,40leration 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 u3ha 1eau..qc 4ylr g)rpward with a speed of 14 m/s on the surface of planet X where the ac ruh.a.rl 1a3) yq4gecceleration 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 +7: eh2fw6abnaxnt* u than 0.10 s. If your friend holds a ruler between your fingers and releases it without warning, how far can you expect the rulb:2etnxa7a w un6 h*+fer to fall before you catch it?

  A ball is thrown upwar;wrz 21xi;cohd at a velocity of 19.6 m/s. What is its velocity after 3wch;o21 ;i zrx.00 s?

  A bullet shot straight up returns to its starting point in 20 s. What is th r7xsz: ,mfer3e initial sp7,r3f xz:sre meed of the bullet?

  A ball is thrown straight3sd y+yvew0rvb79s7 5trydq f3gy 5 o6 up with a speed of 36.0 m/s. How long does it take to re9ft55yryw33 7y 7rv odgy0 + ebvs6dsqturn to its starting point?

  A ball is thrown downward from the top,m7v xoqk3. y5shflp5x*k ,xx of a building with an initial speed of 8 m/s. It strikes the ground after 4.2 s.q.5 s5kp mxx xyf,kh3*l7,oxv How high is the building?

  A ball is thrown straight up wite0lurji -/.p ic(,hpp.gtau 0 h a speed of 30 m/s. (only fill in numerical value in0 ip.thlg0 e pa.,(r/p-cuiju 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 with a sp *ayx 5xy/ t1ugcxkpu5 ek7((l ve:wx/eed of 32.7 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 1 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 the velocity at9 dsrzjod.29q t = 1.0 s?

  In Fig. below, what 0)l khn;btqv d0c* uqo-+xlj5is the velocity at t = 2.5 s?

  In Fig. below, what is the velocity at t = 4.0gdt-a4f cvk8:zru 4 -n s?

  In Fig. below, what is the velocity at t =h 4)n,ckkyz /s 5.5 s?

  In Fig. below, what is the average velocity frt4pb(a )v( (kuemigu0 om 0 to 4.0 s?

  In Fig. below, what is the average io2eaui v,,9m9iyw9l w.n i5dy,*ujyvelocity from 0 to 6.0 s?

  In Fig. below, what is the acceleration at 1.0 s? 2v2gjqt6mzysf 8 kw6)2kvu *r

  In Fig. below, what nr j(( 8 ,atk-yy:gvxtis the acceleration at 3.0 s?

  In Fig. below, what is the average acceleration fromce-qr y,g(33u w1brgm 0 to 5.0 s?

  In Fig. below, what is the averageo5a 0 k0cjxu 0y-u kg/d2en.nx acceleration from 0 to 8.0 s?

  In Fig. below, what is the d h)jcrgisw/ 37q;,jhrisplacement from 0 to 8.0 s?

Does a car speedometer me,.0igy mi 6v1kzs vtl/asure speed, velocity? {speed|velocity}

  An object can have a varyin 2yr7d4 b-puonfo2 k010o;wnl s zh1mtg speed if its velocity is constant.

  The velocity of an object can be negative when its ac.rpe, ff( ipf1celeration is positive.

  If one object has a greater speed than a second object5fbzk4+/v 4 dl;pc;,woz mjou, the first must have a greater accev, ;czl4;wom/ dkp u 4jzf5bo+leration.

  Two cars emerge side by side from a tunnel. Car A is travelib-se rb vs*8/,, lffneng 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 accel b;pl;1ja2u vferation decreases.

  A baseball player hits a foul ball straight up ix)a5 g .cweg* q6yrtk;nto the air. It leaves the bat with a spe tk er)a5g.xc*6qywg; ed 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 happening to its ac7:tf z 6.timqhceleration, how does it change if air frictiot .iqmz7ht:f6 n is ignored?

  As a freely falling object speeds up, what is happening to its acw2ex tzju z3wnng2,o;- fl/7vceleration, how does it change if air frj;nw/ vgu -z3tfn2 ew2,lz7xoiction CAN NOT be ignored?

  An object that is thrown vertically upward will return to its original por 3 :ii/qmih49z,sv imsition with the same speed as it had initially if air resistance is negligible. If air resistance is appreciable, how/m9 isq hi4izv,i:rm 3 will this result be altered?

  An object can have zero velocity and nonzero accelerat2ayn) fx:5i liion at the same time.

  An object can have nonzero velocity and zero acceleration at the samey01ttrw. a-ivx.t1 yu time.

  An elevator moving from the second floor to the fifth floor making no sto n wxjkdqovli 8kfb*jw)7-hv6pv6/ da.14aw ;ps along the way has zero accelerationiw7dxw po jajwd.) fv1k a;*q6n v84/6bkvlh- all the time.

  A rolling ball moves fromi/nl .v9zl )8vz bsvp)zy4oz q.2b-4 ply+mni $x_1=2.7 \mathrm{~cm}$ to $x_2=-7.5 \mathrm{~cm}$ during the time from $t_1=1.7 \mathrm{~s}$ to $t_2=5.5 \mathrm{~s}$. What is its average velocity?  (数值)  $cm/s$ (only fill in numerical value please)

  A particle at $t_1=-3.4 \mathrm{~s}$ is at $x_1=2.6 \mathrm{~cm}$ and at $t_2=3.7 \mathrm{~s}$ is at $x_2=7.8 \mathrm{~cm}$. What is its average velocity?  (数值)  $cm/s$

  A person jogs eight complete laps around a qu ek 7omgf**,kf0bwz t)arter-mile ($1 \; mile = 1609 \; m$) track in a total time of 11.6 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 straig r4wt.uy,jd4fz; +(8kobv ozvht line, moving 103 m away in 10.3 s. It then turns abruptly and gallops halfway back in 4.6 s. Calcuv +d z;, y(zkvrt44ouow bf8j.late (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 frox r:dwt/c4 c-bm $12 \; m/s$ to $23 \; m/s$ in 5.5 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 from2-czlr q)o4jl $17 \; m/s$ to rest in a distance of 76 m. What was its acceleration, assumed constant?  (数值)  $m/s^2$

  A light plane must reach a 86wccxytr* s-speed of $31 \; m/s$ for takeoff. How long a runway is needed if the (constant) acceleration is $2.5 \; m/s^2$ ?  (数值)  $m$

  A world-class sprinter can burst out of the blocks to elr+wg tn19j s .t5m0pxssentially top speed about95ml 0n1 gj.r tpswt+x $10.9 \; m/s$ in the first 10.3 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 o 7y. sizh w8f-1otqx81qak +jvf $15 \; m/s$ to rest in 4.66 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 highway. dxrv4 j o khew0i1+;e3Assuming a decelera+jw ihed0kr;1v ox43e tion of $7.00 \; m/s^2$, estimate the speed of the car just before braking.    $m/s$

  A car is behind a truck going ac -8mz*cz(uv4jiprrhz:4 i 0$25 \; m/s$ 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).    $m$