Is it possible for an object movin c9)16fsyou53nbco8c;w mfbzg with a constant speed to accelerate? Explai; 6ccos8b fm3nw5b)1cyfuz9on.

  Consider a particle moving with constanuof tcsa+,+c 1o: .xpx- zykpq8p 2*hkt speed such that its acceleration of constant magnitude is always perpendicular to its ve2 ysxahk8cq zpt:p+ uok,+p-c fo.x 1*locity.

  An object moves in a circular path ati bzs hl cer:*,j3z;u5i 3x2 sxwo5.zm a constant speed. Compare the direction of the object's velocity and accc.:js r; 5xbuomiz*w2 hixz s,l ez353eleration vectors.

  When an object experiences uniform circ8 0+p(8s 5phttp hxgkzular motion, the direction of the acceleration it zxt8pp 5g8sh(h+0pks

  Consider a particle moving with constant sqn8e 6lf b11bppeed such that its acceleration of constant magnitude is always perpendicular to it 8enb1bf 1p6lqs velocity.

  What type of acceleration does0-sgq3 riqli ; an object moving with constant speed in a circular path e0l;qg 3rq-iis xperience?

  What force is needed fp-e . z1y:tc/qeb -hpto make an object move in a circle?

  When an object experiences uniform0v5/ccdxm rwq e yf25 w2qt:f- circular motion, the direction of the net force ew5 f:5qrw2 -m x/cf2tqdvyc0 is

  A roller coaster car is on a track t5q,nsyx+3ybpva ir;) hat forms a circular loop in the vertical plane. If the car is to just maintain contact with track yrnp,s +bx3y5 i;vqa)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 95miw 6gip36y34izm ddaolw2circular loop (radius = r) in the vertical plane. If the car is to just maintain contact with the track at the top of the loop, what is tho3gil 6 wamz md2y9piw 34i56de minimum value for its speed at that point?

  A pilot executes a vertical dive then followswrq5i c2, + gm0psno9o37qwrr a semi-circular arc until it is going straight up. Just as the plane is at its lw0w 5sp o2i 9mnrg,3+qcrrq7 oowest 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 curve of radius t1 (p *+z8wz wt41m( zitz:govgd) jss$r$ 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 a(lf0hh s-pngk 5-e w0b9,xaj speed v. Then it goes 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 firnp0h eakxsf- j50(wab- l,h9g st time?

  A car goes around a curve of radius r at a constant speed v. Then it g2m nv1dpxi n 3um7b1rde -3pr0oes around a curve of radiu pm2nn1i703v 3ru1e-dmbpr dxs 2r at speed 2v. What is the centripetal force on the car as it goes around the second curve, compared to the first?

  A car of mass m goes around a banked curve of radius r with speed v. Iwok2* +q)ikoqde) e, p+qr; msf the road is frictionless due to ice, the car can still negotiate the curve if the horizontal component ofeqikqk)+qw+ d,)s oe;mrp*o 2 the normal force on the car from the road is equal in magnitude to

  Two horizontal curves on a bobsled run areydz8tm) 3we *k banked at the same angle, but one has twice the radius of the other. The safe speed (no friction needed to *twkm3e8dyz )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 track9 (xoyphs)uz9j( g, nl is not constant, but increases upward from the horizontal(uj 9zp hylg)(oxs,9 n. Coming around a turn, the bobsled team will intentionally "climb the wall," then go lower coming out of the turn. Why do they do this?

  Is it possible for an o94w7 ub8h lk:rqye/xkbject moving around a circular path to have both centripeta8rb/ek wxy uh9 :7q4lkl and tangential acceleration?

  The gravitational force between two objects is pro7 (cabdui.kkn2: 7p krportional to

  The gravitational force between two objects iskng ;bh+ v ijkvy;za;. 8nd2n* inversely proportional to

  Two objects attract each other gravitationally. If *ftt68l:gl*zg8r3 ajm:yw gm the distance between their centers is cut in half, thej *mty t8mlf*8za:g3 r6 gg:lw gravitational force

  Two objects, with mas htabikzuk9j:eb/46(vw4o o (f n:8lz ses $m_{1}$ 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 ma 2ie .iwukw23*gs hh vm. 2(+:rstlkjisses $m_{1}$ 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 gravru,o-7wel ;ti itation.

  Compared to its mass on the Earth, the mass of an object /z1yb d6co ii*8wgh:m rt *,lson the Moon is

  The acceleration of gravity on the Moon is one-sixth o oz5pa0dh6 5kgq-) tzw(zu1 hem0s:d what it is on Earth. An object of mas6(o)o w15 shh -dzp5z d0utmaz:0qkges
72 kg is taken to the Moon. What is its mass there?

  As a rocket moves aw c8 4dqnwd)qahv;1 q6day from the Earth's surface, the rocket's weight

  A spaceship is traveling to the Moon. At what point is it beyond) k4)3kjup6pgmc 3lrjvh- oxhmnz9 4 + the pull of Earth's graml 36-p)3 4ujm krzk xo4pn)hjv+h9gc vity?

  Suppose a satellite were o:m *yk nk9j )+pht)b(z 9ykhu uypw0-jrbiting the Earth just above the surface. What is its centripetal k0n ) p+uy *9uk ht:9zmhpy(k jw-bjy)acceleration?

  A hypothetical planet has a mass of half that of sdphg 7si2-sx/ ss,l vrsj:74the Earth and a radius of twice th77 pvs:d2- 4lhsir,sxj sssg/at of the Earth. 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-sixth what it is on Earth. The r*4l w2r :tqqzxi4z av3a z3 *qiatwlr44vqx2z :dius 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, b( r58etg pyw:iut planet B has twice the radius of plary:gp8 e twi(5net A. If planet A has mass m, what is the mass of planet B?

  Two planets have the mdm:k+m71(gtou b .io0 n4jvisame surface gravity, but planet B has twice the mass of planet A. If planet A has radius r, what is thegb(17:ojo+ n 4dk.mii tvm0m u radius of planet B?

  Consider a small satellite moving in a cirn 4c7lc* qzog-cular orbit (radius r) about a spherical planet (mass M). Which expression gives this satez n*olc 47qgc-llite's orbital velocity?

  Satellite A has twice the mass ofwo)1m4pc.mxi x( 6 h (,vnoqrv satellite B, and rotates in the same orbit. Compare the two satellite's v ivm46 1ro.mxxp hqno( ,w)(cspeeds.

  A person is standing on a scale inhxt/21ohknl0 yf *ajqnr a;u)1pjd0 * an elevator accelerating downward. Compare the reading on no2x* pkan)rf0q/ ; 01ua *hj1ht dlyjthe scale to the person's true weight.

  Who was the first person to realize that the planets move in m/a/ cq0smge1elliptical paths around th1 eqcma sg/0m/e Sun?

  The speed of Halley's Comet, wh6)1,el3qj hmy k v wythru+35n4 -vrzoile traveling in its elliptical orbit around the 6 h ,z-y)wj3 u3lo +1tq5eryv4mhkrnvSun,

  Let the average orbital radius ofpx xih8iqd;ur 57-n k, a planet be R. Let the orbital period be T. What quantity is constant for all planets orbiting txpi-; r u5 k8q7ixhdn,he Sun?

  A planet is discovered to orbit around a stu urq2wpb+qy:(j bxv,* z3q,gar in the galaxy Andromeda, with the same orbital diameter as thx:ujrq *qg3w, bv+(2b,p q yuze Earth around our Sun. If that star has 4 times the mass of our Sun, what 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 Sun is defined as ) qdt mq 1n p/jl+fs4x8r48sczone "astronomical unit" (AU). An asteroid orbits the Sun in ds 4r1mxzfpt4 /q)lcjqns+8 8one-third of a year. What is the asteroid's average distance from the Sun?

State Kepler's laws. 8ew/qr/dq0 zd*j1urd n h1xl8

  List the four fundamental forces in na.z/ lj qqxww:x5gcbl a;)m6q7 2:ryzhture.

  An object moves with a constant speed of 30 m/s on au7,xays wq my.f qc4+. circular track of radius 150 m. What is the acceleration o.+x q4f y7asmuy.wqc ,f the object?

  The maximum speed arn 1p6;cb:2xdtvr u/od ound a level curve is 30.0 km/h. What is the maximum speed around a curve with twice the radius? (Assume all other factors remai2/ udvpdt 1 nxco;r:6bn unchanged.)

  What is the centripetal acceleration of a point on the perimeter of a .ilww2( nr7nc0ic5 mvbicycle wheelin.nicl(c 70vww2m5r of diameter 70 cm when the bike is moving 8.0 m/s?

  A point on a wheel rotating at 5.00 rev/s is located 0.200 m from th6df xs x0k/ gu..sl8k69aud z p5fhi,je axis. What is the centripe6/ if.zxx juk9,ss ulp.0fkdh6 85gadtal acceleration?

  How many revolutions per minute must a circjd4onek/;i -y c3zp-pular, rotating space station of radius 1000 m rotate to produce an artificial gravn pke p i-;o3cy4d-/jzity of $9.80 \; m/s^2$?

  A motorcycle has a mass of 250rw)t2fnlc fe8mpkoji 4d 9+-(3j tv u8 kg. It goes around a 13.7 m radius turn at 96.5 km/h. What is the centripet-fv cdrflik)3m4jt(2nj 8oe9upw t8+ al force on the motorcycle?

  A 0.50-kg mass is attached to on,8vr)aha 2 *6a6vr2ch kw rhthe end of a 1.0-m string. The system is whirled in a horizontal circular path. If the maximum tension tha rkh vron8*2h,ar)aa2wvc 66ht 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 (*7wbxlezn 0, v/mwhaand 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 weight. The stone's spbnmezh(la */w70xw v,eed at this point is given by

  A stone, of mass m, is attached to a strong string and whirled in a vertfwk;ry.i(q x nu-gv5 ;ical circle of radius r. At the exact bottom of the path the tension in the string is 3 times the stone's weight. The ;-( wyx5ik; nrguq.vfstone's speed at this point is given by

  A jet plane flying 600 m/s experiences an acceleration of 4g when pulling out of3n3i a ozurq/1f wlu8wzo.)*f the dive. What is the radius of curvature of the lo8z)rwzo/au n 1 oq.u*wf33i flop in which the plane is flying?

  A pilot makes an outside vertical loop (in which the center s7 p6z :l ss.*lclv0xnof the loop is beneath him) .n0sl* lc:s7z pxlsv6of 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 is he going?

  The maximum force a pilot can stand is abo.idc)1 eqn2nyaihpf, 3t+u+ei7uq6f ut seven times his weight. What is the minimum radius of curvature,e6nqynai1+d u.hic)7upf3q2i +fe t that a jet plane's pilot, pulling out of a vertical dive, can tolerate at a speed of 250 m/s?

  A car traveling 20 m/s rounds an 80-m radius horizontal curve with the tires gl+nk2l2,qzpv(adw 4on tha42d, l(qv+ pzln2 wgke verge of slipping. How fast can this 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 with a speed ov 9j*pz 7jzpa 7;p:idrf 20 m/s. The centr zjzj p: d9rp*77paiv;ipetal force 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 of 14 m/s. Wl.r;d:q7 njhyq ft n f(75,bpghat must be the minimum coefficientt.fjn : (l5f,q dhbg7qp;ynr7 of friction between the tires and the road for the car to make the turn?

  A car is moving with a nd/.jsmvl 8h; constant speed v around a level curve. 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 v;j8d sl nhm./to stay on the road?

  What minimum banking angle is required for an Olympic bobsled4 my 4 :a2fxj11lb)zyqf ish(d to negotiate a 100-m rad) f ymhsja21(qlb4:x fizd14yius turn at 35 m/s without skidding? (Ignore friction.)

  A horizontal curve on a bobsled km)v3gol3 9lm run is banked at a $45^{\circ}$ 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 radius9d4t6rpf2 k ye 100 m, banked at an angle of $45^{\circ}$, may be safely negotiated at a speed of

  A curve of radius 80 m is banked atn/ms(:rw w hr hm2 de*4cspxqeivkc3 )b+5 j-: $45^{\circ}$. 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 unifornu tny0,m 5g3q; *+0 jmffhlpj;fftx8mly in a horizontal circle of radius 0.5 fqf08,0x3 yffj;n lhm*;gn +ptmut5j00
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 accele1-3 qefck xpu9rates at a uniform rate to a speed of 45 m/s in 15 s, moving on ak-fe u1px q9c3 circular 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 of a pd o-3tz :mwk8hroton 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 standing 6leez( g-f/haizj/ +sk:l4wo on the Earth, due to the Moon? sz h:(lzo-elwa/6f+g/i 4k je The mass of the Moon is $7.36 \times 10^{22} \; kg$ and the distance to the Moon is $3.82 \times 10^{8} \; m$.

  The gravitational attractive force between two kq:wflel,sl r)408jyg z1rb3 masses is F. If the masses are moved to half of their initial distance, what is the gravitational a1j,lbr l04elyszqkr f g3: 8)wttractive force?

  For a spacecraft going from the Earth toward the Sun, at what distance from theslj6dyln4 o+uz7p( 1h Earth will the gravitational forces due to the Sun andh4+us j n7dyl1p 6l(zo the 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 rl -gf87hpcqs,k45dh* hin m,is $7.4 \times 10^{22} \; kg$ 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 hos+e476ce 3idkrc-x Earth equal to the radiurs-chx+d3oie6c ke74s of the Earth. What is her acceleration due to gravity?

  The radius of the Earth is jb46juu +y2o8fy+ fenR. At what distance above the Earth's surface will the aub+yo4f6fj 8+j2yn uecceleration of gravity be $4.9 \; m/s^2$?

  A satellite encircles Mars at a distance above its surface equal to 3 times thw wx+k9jw/;60b dl b wt9(lalre radius of Mars. The acceleration of gravity of the satellite, as compared to the acceleration of /bj;9r 0w9kt( bwlwlwlx da6+gravity on the surface of Mars, is

  At a distance of 14000 km from some planet's center, the acceleration of grat4yh58j- wsao vity is 8oa-shy4 twj5 $32 \; m/s^2$. What is the acceleration of gravity at a point 28000 km from the planet's center?

  An object weighs 432 N on the surface of the Earth. The Earth h/ v/pzgmcn:s:as radius r. If the object/nmz/v:p :g cs is raised to a height of 3r above the Earth's surface, what is its weight?

  By how many newtons does the weight of a 100-kg person change whrucs7n, vo6lj:( mwh9e .lhu4 r00 o4qa6mmsyen he goes from sea level to an altitude of 5000 m? (Ths9y h6jclror60 4,e auuw.sq(l:hom7nv m40 me mean radius of the Earth is $6.38 \times 10^{6} \; m$.)

  The Earth has radius r. A satellite;de// 1mryj)cr ws5t e of mass 100 kg is at a point 3r above the Earth's surface. What is the satellite ye5)s/;em ctwr /1jrd's weight?

  A spherically symmetric planet has four times the Ea4xg m ij bpilz4;t*v84rth's mass and twice its radius. 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 pmpj4ti 4z ;xbl 4*igv8lanet?

  During a lunar eclipse, the Moon, Earth,6 rerlb4jqu r 5i0zn,) and Sun all lie on the same line, with the Earth between the Moon and the Sun. The Moon has a mase4 6qr)0rijz,un rbl5s 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 is transpb:+90mmzn d pv0as8b 0bc1gb. x)fjjh orted 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 (it 3ni 7w/xzy*r zh,my-.e., it just skims the surface of the Earth). What is the speed of the satellite? (The mean radius yit,/ xymznz7h3r- w* of the Earth is $6.38 \times 10^{6} \; m$.)

  A satellite is in a low circular orbit about the Earth (i.e., it just skims thcme26bx //wu4 vg3tba e surface of the Earth). How long does it take to make one revolution around the Earth? (The4t e/v 2 b6acu3bxmw/g 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 Eartkg;lp1w 9t8 nlh. It is obswlk1t9g pn l;8erved to have a period of 89 min. What is the mass of the Earth? (The mean radius of the Earth is $6.38 \times 10^{6} \; m$.)

  Europa, a moon of Jupiter, has y0uiz0pac*rm ef( m4 -an 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 Jupil eux))axi3b *ter orbits the planet 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 planet in nearly circular orbits. Moon A has orbital radius xuchk- qg ac/ (/7nur9lzpl.. r, and moon B has orbit/grp/.ucl9.q 7nac ukz h(x- lal radius 4r. Moon A takes 20 days to complete one orbit. How long does it take moon B to complete an orbit?

  The planet Jupiter isz*cdmbuo( g2k+yr)hu2 9rb r2 $7.78 \times 10^{11} \; m$ 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 the average c g,kor nv/1o9distance from Jupiter to the Sun? (The distance from the Earth to thk1v/,no roc9ge Sun is $1.5 \times 10^{11} \; m$.)