Is it possible for an object moving with a constant speed to accelerate? Exs5q(. j(n6k ;ydsvksw plai6dn (sk( yk5 jq;w.ssvn.

  Consider a particle moving (zrw 5 rii5;,ec30 :h zfwhrqvwith constant speed such that its acceleration of constant magnitude is alw hzfw;wrrz5ich,:3 qv (e0r 5iays perpendicular to its velocity.

  An object moves in a circular path at a constant speed. Compare the directiosmg6, hkj34cb sjt+ i)n o sjg mc)s,h+ t63ij4kbf the object's velocity and acceleration vectors.

  When an object experiences uniform circular 8u xo q8er6nz :i*z7axmotion, the direction of the acceleratioa8 7re 8nxzizq :x6u*on is

  Consider a particle moving with constant s,7:ih oik2avd peed such that its acceleration of conv:aik ,i2d7o hstant magnitude is always perpendicular to its velocity.

  What type of acceleration does an object moving with constant st; 6tm m+m+h6mo6nvg gpeed in a circular path experi6+mmt vt ;+ommg ng6h6ence?

  What force is needed to make an object move in a cesq ,-kd.pa4* wtt8 +6jg ,yglivqh( rircle?

  When an object experience.c 3u,jkv iz mq-zo5.js uniform circular motion, the direction of the net force imvz3 , zj.k 5iqc-.juos

  A roller coaster car is on a track that forod,gqim 9org(g6 -4o7uum4zyuieb:4 ms a circular loop in the vertical plane.eru(i uy,mzbo4 :u4 4im9-qgd go7 g6o If the car is to just maintain contact with track at the top of the loop, what is the minimum value for its centripetal acceleration at this point?

  A roller coaster car (mass = M) is on a track that forms a circular loop (raja.qpe48y:3ure+o hd dius = r) in the d+3a:op4 e ujrhe8y.qvertical plane. If the car is to just maintain contact with the track at the top of the loop, what is the minimum value for its speed at that point?

  A pilot executes a vertical dive then follows a semi-circular arc untilwk r))d:ux /lz 9dysv*dgy-y/ it is going straight up. Just as the plane is at-d dws/dl)y)9/vxy :*ruy zkg its lowest point, the force on him is

  A coin of mass $m$ rests on a turntable a distance $r$ from the axis of rotation. The turntable rotates with a frequency of $f$. What is the minimum coefficient of static friction between the turntable and the coin if the coin is not to slip?

  A car goes around a ) dqe pc9g7c7x;(iz 1wzeja9d curve of radius $r$ at a constant speed $v$. What is the direction of the net force on the car?

  A car goes around a curve of radius r at a constant speed v. Then it g-dkh-f6-lg b nb9h: zwoes around the same curve at half of the original speed. What is the centripetal force on the car as it goes around the curve for the second time, compared to the fir9hn6 l:k-zb gb -wdfh-st time?

  A car goes around a curve of radius r :z7)4, m q cdnc3ob-dink4bssat a constant speed v. Then it goes around a curve of radius 2r at speed 2v. What is the centripetal force on the car as it goes around the second curve, coms -)k ,zq4b7nnbs4id 3cmco:dpared to the first?

  A car of mass m goes around a banked curve of radius r with speed v. Ifm 8p(vxjozd ws:deoe*.f38q . the road is frictionless due to ice, the car can still negotiate the curve if the horizontal component of the nomd83z(swje .dxeopo.fq:v 8* rmal force on the car from the road is equal in magnitude to

  Two horizontal curves on a b25wmycg d76 h+6b rmzmyii:-kobsled run are banked at the same angle, but one has twice the radius of the ot:wy6r5 czh dk mmi-bg2m+yi67her. The safe speed (no friction needed to stay on the run) for the smaller radius curve is v. What is the safe speed on the larger radius curve?

  The banking angle in a turn on the Olympic bobsled track is 9fr6x( 1er snwnot constant, but increases upward from the horizontal. Coming around a turn, the bobsled team 9r 6wxf (e1snrwill intentionally "climb the wall," then go lower coming out of the turn. Why do they do this?

  Is it possible for an object moving around a circulan7,eh 46adtoj j z9bq4gp;p 0or path to have both centripetal and tangentipq 4eh7abjn 6 0o4 ozptdj;9g,al acceleration?

  The gravitational force between two objects is 1ig sdvv 9rwj1*+b a2iproportional to

  The gravitational force between two obje,rlp ,cq ue(j)cts is inversely proportional to

  Two objects attract each other gravcs9y-*uo6n+ bp;ifc5 v,tyj oitationally. If the distance between their centers is cut in half, the gra;*y - tc,nipyvou5j9s+cbo6fvitational force

  Two objects, with mave2j/n z. b zq5)vr3vvsses $m_{1}$ and $m_{2}$, are originally a distance r apart. The gravitational force between them has magnitude F. The second object has its mass changed to 2$m_{2}$, and the distance is changed to r/4. What is the magnitude of the new gravitational force?

  Two objects, with masse+on -hgb-w6xjtk (beik5 jw1xgt,; *xs $m_{1}$ and $m_{2}$, are originally a distance r apart. The magnitude of the gravitational force between them is F. The masses are changed to 2$m_{1}$ and 2$m_{2}$, and the distance is changed to 4r. What is the magnitude of the new gravitational force?

State Newton's law of universal gravi1 gm9ceq3fytfk:6e5ytation.

  Compared to its mass on the Earth, the mass of an objecgc4c w1 imr *-cgz1q3t+9giwst on the Moon is

  The acceleration of gravity on the Moon is one-sixth what it is on Earth. Aaw l2nl(y-k71f6t)w ku 8n wjfn object of mass7ljyna1wk kl6ffw n 2t8()-w u
72 kg is taken to the Moon. What is its mass there?

  As a rocket moves away from thev teab0vw7 tlp48y d(4 Earth's surface, the rocket's weight

  A spaceship is traveling to the Moon. At what point is it bsi 2ra9zy() xveyond the pull of Eartyza )xvi( r29sh's gravity?

  Suppose a satellite were orbiting the Earth just above the surface. izw*l1;.szf3 v1 vs*,jo gykwWhat is its centripetal afw *v k,1. jgsw3l*y1ov;zizs cceleration?

  A hypothetical planet has a mass of half that of the Earth a h f 7op1la6mg:h-/kzufp/f*z nd a radius of twice that of the Eaf1u flaf/h7: 6zg/*zp -o mhpkrth. What is the acceleration due to gravity on the planet in terms of g, the acceleration due to gravity at the Earth?

  The acceleration of gravity on the Moon is one-sixtqxb-w p7/3e xuh what it is on Earth. The ru/xb7x qwe -p3adius of the Moon is one-fourth that of the Earth. What is the Moon's mass compared to the Earth's?

  Two planets have the same surface gravity, but planet B has twice the ramf.5h; 5dwzrkk4g/* al h*n ybdius of planet A. If planet A has mass m, what isg4fh*kdn;wb*kl. zm hya5 5 /r the mass of planet B?

  Two planets have the same surfaczhz( f) 8.mveee gravity, but planet B has twice the mass of planet A. If planet A has radius r, what ( . vehez8mzf)is the radius of planet B?

  Consider a small satellite movigc1.kxh vb v45 ap6 *vy*fnwur3 +tt7kng in a circular orbit (radius r) about a spherical planet (mass M). Which expression gives this satelltwg1vu+ bx* 64 v kfn7 *k5hta3ycprv.ite's orbital velocity?

  Satellite A has twice thek y)clh x40ad7ztg z() mass of satellite B, and rotates in the same orbit. Compare the two satellitex4z0chzy(t) g7ka)d l 's speeds.

  A person is standing on a scal1uk7pg f vb;*y1vwr8qe in an elevator accelerating downward. Compare the reading on the scale to thepwykbq;*f1vv8gu1 7r person's true weight.

  Who was the first person to realize/*hz. pz5 2lx,i a qhbu2( czkb;7vllf that the planets move in elliptical paths arozb xhl a2.;5l lbzv chk(*p/7z2if uq,und the Sun?

  The speed of Halley's Comet, while traveling in its elliptical orbw2nq 2xj wg0uarn,. chz-z*n) it around the Swq0wr2zjgn2.,czu h- xa)n n *un,

  Let the average orbital radius of a planet be R ogov:bi1wb6ocrh9ew76 +n3mejx* ifz)x c*,. Let the orbital period be T. What quantity is constant for all planets orbiting the3e m*,+o9xjb*vwhbo ri 6w 6o 7zeixfgcc:)1n Sun?

  A planet is discovered z6s gwf)0 qgd;qr.co )to orbit around a star in the galaxy Andromeda, with the same orbital diameter as the Earth around our Sun. If that star has 4 times the mass of our Sun, whao 0g.q;q)dfrwc gzs)6 t will the period of revolution of that new planet be, compared to the Earth's orbital period?

  The average distance from the Earth to the Suni83nwvyqqi6 , is defined as one "astronomical unit" (AU). An asteroid orbits the Sun in oninw68 y qiq,3ve-third of a year. What is the asteroid's average distance from the Sun?

State Kepler's laws.bo vqs)-j; b,m

  List the four fundamental forcesardzr79( b2zns+4 mx q in nature.

  An object moves with a constant speed of 30 m/jt fq.r:/vo4jopfw/( *gliru0s0/mr wbqh84 s on a circular track of radius 150 m. What is the ac pwro0ljo f4jb/4i/h8r:/.g f0qurmq(v ts w*celeration of the object?

  The maximum speed around a level curve q0(do u,kbsq7*0eta mis 30.0 km/h. What is the maximum speed around a curve with twice the radius? (Assume all other facto0ksd (tq boaq *7e,m0urs remain unchanged.)

  What is the centripetal acceleration o3q( s:xfxh jm(mqc(i jt*1 j7pf a point on the perimeter of a bicycle wheel of diameter 70 cm wqjm:1(hp xjj 3itq*f( cx m(7shen the bike is moving 8.0 m/s?

  A point on a wheel rotating at 5.00 rev/s is loyt h j;;)omp z;)i)oaicated 0.200 m from the axis. What is the centripetal accelerat ay))oimhzp)j;;i; toion?

  How many revolutions per minute must a cirazqmhv( j(1:acular, rotating space station of radius 1000 m rotatevqzjam (:(ah1 to produce an artificial gravity of $9.80 \; m/s^2$?

  A motorcycle has a mass of 250 kg. It 80a+p9bhap m0*c auwlgoes around a 13.7 m radius turn at 96.5 km/h. What is the centripetal force oncpu+ 00mb 9aaap8 wlh* the motorcycle?

  A 0.50-kg mass is attached to the end of.n/ a)x+vsdw(.ggdsqmu*l i/ jc 9p1u a 1.0-m string. The system is whirled in a horizontal circular path. If the maximjvpx +(n g d.gusmcw)1.sild*a/9qu/um tension that the string can withstand is 350 N. What is the maximum speed of the mass if the string is not to break?

  A stone, of mass m, is attached to a strong string a6 okk oaossnepuzwo-+ c6k78 7+2w -cpnd whirled in a vertical circle of radius r. At the exact top of the path the tension in the string is 3 times the stone's wewn+7 -wckzk6o eppkacsoo678s +-2ou ight. The stone's speed at this point is given by

  A stone, of mass m, i,bb7-quex-a s s attached to a strong string and whirled in a vertical circle of radius r. At the exact bottom of the path the tension ibb seax,q -7u-n the string is 3 times the stone's weight. The stone's speed at this point is given by

  A jet plane flying 600 m/s experiences auw ;aov.c++t+vmq5j i0t 8fb4lbg-kc n acceleration of 4g when pulling out of the dive. What is the radius of 8+g0lvqtt4cb+5 -c.b;f+wvm i ajuo kcurvature of the loop in which the plane is flying?

  A pilot makes an outside vertical loop (in kit5.+nh(2tfn jmkk9 z -z e+owhich the center of the loop is beneath him) of radius 3200 m. At the top of his loop he is pushing down on his seat with only one-half of his normal weight. How fast ieh k+ 9-jk.tfzo+ 2mt i5nk(zns he going?

  The maximum force a pilot can stand is about se h4* 2.guoeimj1dci7 zven times his weight. What is the minimum radius of curvature that a jet plane's pilot, pulling out of a vertical dive, can tolerate at aoz. m*c1h7d ej2u4gii speed of 250 m/s?

  A car traveling 20 m/s rounds an 80-m radius zh;o:x9two1f horizontal curve with the tires on the verge of slipping. How fast can t1xof:ot ; hzw9his car round a second curve of radius 320 m? (Assume the same coefficient of friction between the car's tires and each road surface.)

  A car is negotiating a flat curve of radius 50 m rsl kuo8(;repj,m/2e with a speed of 20 m/s. The centripetal forculsk2 o;e(8rp/,re jme provided by friction is $1.2 \times 10^{4} \; N$. What is the mass of the car?

  A car goes around a flat curve of radius 50 m at a speed z9 r mnk5s1l/uw qx+)gof 14 m/s. What must be the minimum coefficient of friction bern5 lgx+ks1)w9q/mu z tween the tires and the road for the car to make the turn?

  A car is moving with a constant speed v around a level cuqimd7xz;wp5 ,rve. The coefficient of friction between the tires and the road is 0.40. What is the minimum radius of the curve if the car is to xmq di;,zw 57pstay on the road?

  What minimum banking angle is required ffxvv6(pxp;u x3rd: m)0on 1ntor an Olympic bobsled to negotiate a 100-m radius turn at 35 m/s without skidding? (Ignore frictionfp(voxnn 6)tv1 rd30x: mp;ux.)

  A horizontal curve on a bobsled run is banked at a fk(nlsp /kt tj0d 1-5l$45^{\circ}$ angle. When a bobsled rounds this curve at the curve's safe speed (no friction needed to stay on the run), what is its centripetal acceleration?

  A frictionless curve of wzeng+7nl0q f a2eh8+radius 100 m, banked at an angle of $45^{\circ}$, may be safely negotiated at a speed of

  A curve of radius 80 m is banl:*oq(uvbo-.tznj+ v /;zmci ked at $45^{\circ}$. Suppose that an ice storm hits, and the curve is effectively frictionless. What is the safe speed with which to take the curve without either sliding up or down?

  A 175-kg ball on the end of a string is revolving uniforgkqf1hg.5iu myp5) s2mly in a horizontal circle of radius2h5k) s1.gi g5mu pyfq 0.500
m. The ball makes 2.00 revolutions in a second. (only fill in numerial value in the blanks)
(a) Determine the speed of the ball.    $m/s$
(b) Determine the ball's centripetal acceleration.    $m/s^2$
(c) Determine the force a person must exert on opposite end of the string.    $N$

  Starting from rest in the pit area, a race car accel 45m cpoues4cauy x ;0o2by9a*erates at a uniform rate to a speed of 45 m/s in 15 s, moving on a ci;2bm94x *uoyos c540epac ayu rcular track of radius 500 m. (only fill in numerical value in the blanks)
(a) Calculate the tangential acceleration.    $m/s^2$
(b) Calculate the radial acceleration when the instantaneous speed is equal to 30 m/s.    $m/s^2$

  The hydrogen atom consists 6yshuow/+(f0mz;/ ,di/ e zfr d3vkfuof a proton of mass $1.67 \times 10^{-27} \; kg$ and an orbiting electron of mass $9.11 \times 10^{-31} \; kg$. In one of its orbits, the electron is $5.3 \times 10^{-11} \; m$ from the proton. What is the mutual attractive force between the electron and proton?

  What is the gravitational force on a 70-kg person standingh6tkxl;nj 46n/b2llb on the Earth, due to the Moon? The mass of the M l 6nkh ;/xlb4jtbl26noon is $7.36 \times 10^{22} \; kg$ and the distance to the Moon is $3.82 \times 10^{8} \; m$.

  The gravitational attractive force blp 5p c0.+l * vmj/qd:lffo8fhetween two masses is F. If the masses are moved to half of their initial distance, what is c/ 5*p0+ mll8dv qofjlf.hpf:the gravitational attractive force?

  For a spacecraft going from the Earth toward the Sun, atr,z (ncfvq* m, f2ibz) what distance from the Earth will the gravitational forces due to the Sun and m,if (vf,2z rcbn z*)qthe Earth cancel?
Earth's mass: Me = $5.98 \times 10^{24} \; kg$ the Sun's mass: Ms = $1.99 \times 10^{30} \; kg$
Earth-Sun distance: r = $1.50 \times 10^{11} \; m$

  The mass of the Moon is ktd61t: /uuok.(pig r$7.4 \times 10^{22} \; kg$ and its mean radius is $1.75 \times 10^{3} \; km$. What is the acceleration due to gravity at the surface of the Moon?

  An astronaut goes out for a "space-walk" at a distance above the Earth equal tqxamz;y+l q/x srt 1/5o the radiusa zl1rm / yqx/x;+qt5s of the Earth. What is her acceleration due to gravity?

  The radius of the Earth is R. At what distance above the Earth's su (syg a1q)ie p:*itk5grface will the acceleratioy5g:teii1( ) kqgpas*n of gravity be $4.9 \; m/s^2$?

  A satellite encircles Mars at a distance above itsy r:n1nfi5:x2:s rx5zdd9ugne, 7 fj i surface equal to 3 times the radius of Mars. The acceleratio9nxi5i: jsd n,f 7:nd2y :rf5xr1uezg n of gravity of the satellite, as compared to the acceleration of gravity on the surface of Mars, is

  At a distance of 14000 :t* .rtg43hk+x4+ r b:ky fvgyohdyd8 km from some planet's center, the acceleration of gravity i.g t h4d4 x8ovrky*dy+k: btfg +rh:y3s $32 \; m/s^2$. What is the acceleration of gravity at a point 28000 km from the planet's center?

  An object weighs 432 N on the surface olj 7/ se0 sofi-js7pivi .8vz*f the Earth. The Earth has radius r. If the object is raised to a hevlvi8esips f i7s.- z0/7* jojight of 3r above the Earth's surface, what is its weight?

  By how many newtons does the weight of a 100-kg person change when he g da *(7)a5ygpv.u w/fnd vv/ut.r7 hxkoes from sea level to an altitude of 5000 m? (The mean radius of the Earth i() /u7.ga.*t/nvd5 yx hdkav pw7fru vs $6.38 \times 10^{6} \; m$.)

  The Earth has radius r. A s +1j1 :d neaw6-pyokigatellite of mass 100 kg is at a point 3r above the Earth's surface. What is the sat61ag-d nk1pjwy+:o ieellite's weight?

  A spherically symmetric plo(j a8atl5. pbanet has four times the Earth's mass and twice its radiu5 pl 8.(otjbaas. If a jar of peanut butter weighs 12 N on the surface of the Earth, how much would it weigh on the surface of this planet?

  During a lunar eclipse, the Moon, Eafjj ,u25 .b)ch8 vywfmhzv 8e,rth, and Sun all lie on the same line, with the Earth between the Moon and the vheyc8fmuz h)fv5b8 w,j. ,2 jSun. The Moon has a mass of $7.36 \times 10^{22} \; kg$; the Earth has a mass of $5.98 \times 10^{24} \; kg$; and the Sun has a mass of $1.99 \times 10^{30} \; kg$. The separation between the Moon and the Earth is given by $3.84 \times 10^{8} \; m$; the separation between the Earth and the Sun is given by $1.496 \times 10^{11} \; m$.
(a) Calculate the force exerted on the Earth by the Moon, its magnitude is    $\times 10^{20} \; N$, its direction is  ----待选择----towardsaway from  the moon.
(b) Calculate the force exerted on the Earth by the Sun, its magnitude is    $\times 10^{22} \; N$, its direction is  ----待选择----towardsaway from  the Sun.
(c) Calculate the net force exerted on the Earth by the Moon and the Sun, its magnitude is    $\times 10^{22} \; N$, its direction is  ----待选择----towardsaway from  the Sun.

  A 2.10-kg brass ball ist ;ei)s qe44gl 2u7(bx ed49l2 grp dehusa8(b transported to the Moon.
(a) Calculate the acceleration due to gravity on the Moon.    $m/s^2$ (The radius of the Moon is $1.74 \times 10^{6} \; m$ and the mass of the Moon is $7.35 \times 10^{22} \; kg$)
(b) Determine the mass of the brass ball on the Earth    $kg$ and on the Moon    $kg$
(c) Determine the weight of the brass ball on the Earth    $N$
(d) Determine the weight of the brass ball on the Moon    $N$

  A satellite is in a low circular orbit about the Earth (i.e.84*w pcpgkf +e(a b;mz, it just skims the surface of the Earth). What is the speed of the satellite? (The mean radius + cmfka;zpg48(e *p bwof the Earth is $6.38 \times 10^{6} \; m$.)

  A satellite is in a low circular orbit abo v.ryl)dz:hh+fft4xz a9/5ufut the Earth (i.e., it just skims the surface of the Earth). How long does it/hy 5tua9xrzz.: flvf+ hf4)d take to make one revolution around the Earth? (The mean radius of the Earth is $6.38 \times 10^{6} \; m$.)

  A satellite is in circular orbit 230 km above the surface of the Earth. It is 3na1jio/-t o ;yqj vijcane +ku3)z2/observed to have a period of 89 min. What is the mass of the Earth? (ajtvo2 1n3i-/ yzn/ u e )j3c+ajiok;qThe mean radius of the Earth is $6.38 \times 10^{6} \; m$.)

  Europa, a moon of Jupiter, has a:d dar 3vb.e.jn orbital diameter of $1.34 \times 10^{9} \; m$, and a period of 3.55 days. What is the mass of Jupiter?

  The innermost moon of Jupiter orbits the plaf qfzzv2+qz*p dx0l )77n*wisnet with a radius of $422 \times 10^{3} \; km$ and a period of
1.77 days. What is the mass of Jupiter?

  Two moons orbit a planet20 m0yzwibdx0 in nearly circular orbits. Moon A has orbital radius r, and moon B has orbital radius 4r. Moon A takes 20 days to complete0x0i dz20byw m one orbit. How long does it take moon B to complete an orbit?

  The planet Jupiter ivemgf08 bx p40o*kr4 ns $7.78 \times 10^{11} \; m$ from the Sun. How long does it take for Jupiter to orbit once about the Sun? (The distance from the Earth to the Sun is $1.50 \times 10^{11} \; m$.)

  It takes the planet Jupiter 12 years to orbit the Sun once. What is l/c3p0f0 rf;7e qhal nthe average distance from Jupiter to the Sun? (The distance ffeql30; raph nfc7/0lrom the Earth to the Sun is $1.5 \times 10^{11} \; m$.)