Is it possible for an object moving with a/nohek-z2 1 fh constant speed to accelerate? Explain.- oenf/zh1kh2

  Consider a particle moving with constant spe85h/ 6pv w r*barru7iv.re.*3a qnl0z4dcq nded such that its acceleration of constant magnitude is always7a6nh qi5rew4vn .v*q/cbz.*8rrlr0 a u3dpd perpendicular to its velocity.

  An object moves in a c*o.3o6n i 8 q:pctdr.sze 0uyiircular path at a constant speed. Compare the direction of the object's velocity :ue6t*zsq3p onr ii.y do.0c8and acceleration vectors.

  When an object experiences uniform circular * zo uck iik4n:yy26q;motion, the direction of the accelezn6:;iy4i* koq2 kuycration is

  Consider a particle movingmxf f0m+60(pimmtmm+ r d)cr5 with constant speed such that its acceleration of constant magnitude is always perpendicular to its vedm+ p( m0trr5 mmfmif)m6x+c 0locity.

  What type of acceleration does an object moving with conrajiv v)+9+ocstant speed in a circular path e +v)covi9j +arxperience?

  What force is needed to make an objebz5 ze.(dhzn7j (kgx0ct move in a circle?

  When an object experien y)f(v:pq( zrpces uniform circular motion, the direction of the net forcr f y)p:q(pz(ve is

  A roller coaster car is on a track that forms a c8a(9vu y y c 6ihg;qxoda.52wfircular loop in the vertical plane. If the car is to just maintain contact with track at the top of the loop, what is the minimum value for its centripetal accele dy 2uxqwya;h.i 86vo9c 5agf(ration at this point?

  A roller coaster car (mass = M) is on a track that forms au4.x7-ellal+yp+ x (bsz c, gy circular loop (radius = r) in the vertical planezulxg, x.+cy+7pye bll(s 4a- . 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-circular6yw zhyy;e-+u (cuv0l arc until it is going straight up. Just as the plane is at its lowest point, the force on hh 0uy+6z yyc;le(vu-w im 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 o;)ul f y :qov5vv3c*/a5oydn jf 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 r 1q-qhh hlo *zh:6t9kofx j0a*4ceekvs09 6dvadius r at a constant speed v. Then it goes around the same curve at half of the original speed. What is the centripetal*ds0fe- 9e 1k*tk0 vvqalhh66x9hhzj q4 oco: force on the car as it goes around the curve for the second time, compared to the first time?

  A car goes around a curve of radius r at a constant s j6yczxmv;x .:peed v. Then it goes around a cuzxx.;mcj:6vy rve of radius 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.tfwzmz+9/yptwh.a , 9 If the road is frictionless due to ice, the car can still negotiate the curve if the horizontal component of the normal forcezzfta, .py 99+twwm/h on the car from the road is equal in magnitude to

  Two horizontal curves3z3i qke (uxb oni9,4t on a bobsled run are banked at the same angle, but one has twice the radius of the other. The safe speed (no friction needed to stay on the run) for the small3qix4b z(3t uk,eo ni9er 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 not constaw 0 nr woy93x.7b3mtoxnt, but increases upward from the horizontal. Coming around a turn, the bobsled team will intentioxor7nxmw.w0 boty 933 nally "climb the wall," then go lower coming out of the turn. Why do they do this?

  Is it possible for an object movi-*+m r9umqd;aab (8m)75fx hpjzcewcng around a circular path to have both centripetal and tangential accelerati9emh )q-cfzprw 8aa( +c;umjm b7* 5xdon?

  The gravitational force between two objemnit 3+2rgr9tcts is proportional to

  The gravitational force between two objecth2d k9mbh,m*y s is inversely proportional to

  Two objects attract each other gravitationally. If the distance betw7ho cf2x+ 9k;r8:sqygn;6jvel- kmgoeen their centers is cut in +q;f-lvj g7s 2o:x9on;6k8mce y grhkhalf, the gravitational force

  Two objects, with masses e+yj z8vqlhkv3u3 3j +$m_{1}$ 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 masseoy y e3wlmyy(h ;k ud6;qc8*h1s $m_{1}$ 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 grav +vhtnenufy40i h22) aitation.

  Compared to its mass o0dic 45tb/myc th:oguu/ p m.;n the Earth, the mass of an object on the Moon is

  The acceleration of gravicq 3n: zqhq5ka1- (s5,ps lsmyty on the Moon is one-sixth what it is on Earth. An object of masakqz-psc q5,ss q1ym53( n l:hs
72 kg is taken to the Moon. What is its mass there?

  As a rocket moves away2bhq1b4fo8l8 cronk * from the Earth's surface, the rocket's weight

  A spaceship is traveling to the, sa 4t)tw2rin Moon. At what point is it beyond the pull of Eartrat n,2st)wi4 h's gravity?

  Suppose a satellite were orbiting the Earth just abo8.5 smo g2,qkolpr f(lve the surface. What is its ce2p(fqg,ml8 solr .o5kntripetal acceleration?

  A hypothetical planet has a mass of half tha6l1c mfna3*g,(a4izgfob zs7t of the Earth and a radius of twice that of the Earth. What is the acceleration due to gravity on the planet in t,(a nbff3g7ocl6*z zmi4 sa1germs of g, the acceleration due to gravity at the Earth?

  The acceleration of gravity on the Moon is one-sixth whahp.ltjhf n;05u5iqzc)8xd0 u t it is on Earth. The radius of the Moon is one-fourth that of the Earth. u0i5ljtxh 5. 0 ;dpq8)hf nuzcWhat is the Moon's mass compared to the Earth's?

  Two planets have the same surface gravity, but planet B has twice the rabv:o. t,i9 vkmdius of planet A. If planet A has mass m, what is the mass of plv ,bom:.kvt9ianet B?

  Two planets have the same surface gravity, but planet sj /- i1q60id3wki nenB has twice the mass of planet A. Ifw3 e-dk1nns/ji6q0 ii planet A has radius r, what is the radius of planet B?

  Consider a small satellite moving in a circular orbit (radius r) aboutohe( 26hn*b.nux ha: zhds wg9xi*i3 . a spherical planet (mass M). Which expression gives this satellite'xnh eg3sao(ixuh h9w*b*2 .i.hz:nd6 s orbital velocity?

  Satellite A has twice the mass wt+r1lspte v oj8x*0+of satellite B, and rotates in the same orbit. Compare the two sx+e8*vp1tjl+ 0o t swratellite's speeds.

  A person is standing onhv1j,xd c v(px24hh(zxqx e5c5p) t, p a scale in an elevator accelerating downward. Compare the reading on the scz, jhdvt 5e,vpxx 4ch(cx25 ppx( h)1qale to the person's true weight.

  Who was the first person to realize that the planets moveaa+z9xr,a7gdzt8/u+nfwc g)-5 g pr h in elliptical paths around the Sun?+a+a,u/f987h wc g a 5-zxrpggd r)tnz

  The speed of Halley's Comet, while j3:sdl9f( nre traveling in its elliptical orbit around the dle fjr :(n3s9Sun,

  Let the average orbital radius of a planet be R. Let the orbital peraludmn yb6n0:e w; a;rs6fnsnxh -.d 7j8)2lwiod be T. What quantity is constant for all planets orbitingn;r7:2;m8d jw e ss66nlx -.ynwbnhaau)0dfl the Sun?

  A planet is discovered to orbit around a star in the galaxyet* m; 6oz7xvf Andromeda, with the same orbital diameter as the Earth around our Sun. If that s*ezmt oxf 67v;tar 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 o k+obkl-y1i7s ne "astronomical unit" (AU). An asteroid orbits the Sun in one-third of a year. What is the asteroid's average distance from tiblk7s o+-1k yhe Sun?

State Kepler's laws.gm /u ym 35vcj:lxf0+j

  List the four fundamental forces in mubrc u3;ej xj)(vuj ,k1n,9rnature.

  An object moves with a constant speed of 30 m/s on a circular+ u6( 1b/ 9.wr yg: b,ohhrgtm6hbqdze track of radius 150 m. What is the acceleration:mg6 6,.oeb r q(+zb/9wrh1g hy dhbtu of the object?

  The maximum speed around a level curve is 3 jg9*,m3 fz9v cbs.mc5axab c c-hzu;90.0 km/h. What is the maximum speed around a curve with twice the radius? (Assume all otheruh; -avfz9b.m399jcsxb czcga m*, 5c factors remain unchanged.)

  What is the centripetal a,0vdc vskc84 ybm,dqrpst5 ,+cceleration of a point on the perimeter of a bicycle wheel of diameter 70 cm when the bike is moving 8.0 mcpcqr t+,d,k4bvsm,v 085d sy /s?

  A point on a wheel rotating at 5.00 rev/s is locat4jz8 yd 5ggx3z l aqw06n vsy+s*uw1-led 0.200 m from the axis. What is the centr6vyslxa 5zg -0wn3gd* wyl4su8q +1zjipetal acceleration?

  How many revolutions per minute must a circular, rotating space pxw( j5 z7 u3c9t m*w2vy(fbf x)kqx-uqxe8i-station of radius 1000 m rotate to produce an artificial gravxu- (xvxk53-8 w)wfiy cz *t7e9u2 qbq(xfpmjity of $9.80 \; m/s^2$?

  A motorcycle has a mass of 250 kg. It goes around a 13.7 m ra1k b 0j3 c4,fsgp6wqardius turn at 96.5 km/h. What is the centripetal3w 1 j6a4grs,0cfkqbp force on the motorcycle?

  A 0.50-kg mass is attac , g w b -f:1t6rkdmjpp+q8.rz(rkhfb7hed to the end of a 1.0-m string. The system is whirled in a horizontal circular path. If the maximum tension thab(h-b:fr ,1.dm6 ftk g7 pr8+pkwjqzrt 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 and whirled in a verticap d3 )f)afjh4l:7hl bmb.lkh- l 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 speed a.fd-phbb h7j:43 akmll) lf)ht this point is given by

  A stone, of mass m, is attached to a strong string and whirled in a vegr ma d-:17ut,qfe6+ x6jsl agrtical circle of radius r. At th 6d6mfge ,jlg7aqxs -u 1:t+are exact bottom of the path the tension in 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 an accelerationaxi (sf1cz e4,n4 xt7n of 4g when pulling out of the dive. What is the radius of curvature n c4zas41fn,ix et7x(of the loop in which the plane is flying?

  A pilot makes an outside vertical loop (ij ym5;khhyatd 8 h;y0kkp5,9sn which the center of the loop is beneath him) of radius5t0kkdjh8 ,y s;p9ykmh; ay5h 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 about seven times his weight. What ikl(gianyvv,z8+ 5yda f +- +vcs the minimum radius of curvature that a jet plane's pilot, pulling out of a vertical dive, can tolerate atalvif5vv+-kyd,+n(az g+y 8c a speed of 250 m/s?

  A car traveling 20 m/s rounds an 8a:6k,b3o f-gqjp- pp c0-m radius horizontal curve with the tires on the verge of slipping. jpb --p,p3g:qk fo ac6 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 q 0ris6rh7 f /j8z;c7 zuzzrx41ke+qnof radius 50 m with a speed of 20 m/s. The centripetal force provid 8rxizhk/1 r j;z0r4e 7nzz qs7qu6f+ced 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. g8a wx:mz* g*w q:(xnqWhat must be the minimum coawx( qn:8:wxqgm *g*zefficient of friction between the tires and the road for the car to make the turn?

  A car is moving with a constan y jeel v+b+jxh0,pn82t 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 ieyp+v x2,ln0+8 jhebjf the car is to stay on the road?

  What minimum banking angle is required for an Olymb p0c: 0t+awtfpic bobsled to negotiate a 100-m radius turn at 35 m/tp:bt0w+c 0a fs without skidding? (Ignore friction.)

  A horizontal curve on b/ ycxhgs+ p1o.:,dqr a bobsled 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 radius 100 m, banked at anem tnk--ec6u7w - x7)tm 7zgdv angle of $45^{\circ}$, may be safely negotiated at a speed of

  A curve of radius 80 m is bankcfd//zecwqh* ogk38*t( eb q; ed 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 uniformly in a m23mwpw- s f*w7dg* k 8ivd)dfhorizontal circle of radwd2kgdi w*d-8mmf 3vsp7* )fwius 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 accelerates at a unifor1ls7b n2wos )sy3jpp2m rate to a speed of 45 m/s in 15 s, moving on a circular track of radius 500 m. (only fill in numerical value in the blanks)3 j71p p)s2ys o2snbwl
(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 cony( w)jf *uuo*ysists of 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 standing on the Earth, due to jy20nj8x 3lyl the Moon? The mass of t8jl y2nyljx03 he 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 masses iov-7kr;z ae 3qt0fip9s F. If the masses are moved to half of their initial distance, what is the gravo z9k3ia ;rqtp-v70efitational attractive force?

  For a spacecraft going from the Earth toward the Sun, at what 64oh5w xi9l0do rkxo.distance from the Earth will the gravitational forces due to the Sun and the Earth id4l hx9o ok x05ow6.rcancel?
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 /zvj2vua fw6d6hv)1 wis $7.4 \times 10^{22} \; kg$ 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 equalxwqo5n1xbfi who-+2j qbb b(6tn-+7n to the radius of the Earth. What is her accefhowj52 b6+n(-bti nowqxb 7 - 1nqxb+leration due to gravity?

  The radius of the Earth is R. At what distance bv ym4k.i lqc+4-j9qh above the Earth's surface will the acceleration o+4yh. qkmilvjcq 49-b f gravity be $4.9 \; m/s^2$?

  A satellite encircles Mars at a distance above its surfqur2qw292e sx p72eu4 c ip4xuace equal to 3 times the radius of Mars. Th972wisxu2cpxq4e4 ru2 upeq 2 e acceleration of gravity of the satellite, as compared to the acceleration of gravity on the surface of Mars, is

  At a distance of 14000 km from some planet's center, the acceleratefqs4a o*+ 2n;l oc4ouv4h;la ion of gravity i;quhonc l +foa24eva*4 l4;s os $32 \; m/s^2$. 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 hasgi9q6) 18rww :lwjtthei*w .e radius r. If the object is raised to a height of 3r above the Earth's surface, what isteijwwqwi9 trw le)*68g1.h : its weight?

  By how many newtons does the weight of a 100-kg person change when he goenq8g g ww3/1cos from sea level to an altitude of 5000 m? (The mean radius of the Ea c/wog8q n3wg1rth is $6.38 \times 10^{6} \; m$.)

  The Earth has radius r. A satellite of massqohd+iv 7cv-,nyn *)jmkd-xgo/y r, 1 100 kg is at a point 3r above the Earth'o/-7 xnkq nmy)dd,1v-, yrig hv+oj*cs surface. What is the satellite's weight?

  A spherically symmetric planet has four times thega+ v) :kx0wyo so,au7w/hj)3k;xoad Earth's mass and twice its radius. If a jar of peanut butter we;kdg7vw oj:0oa s kwa )x h)/uoax+y,3ighs 12 N on the surface of the Earth, how much would it weigh on the surface of this planet?

  During a lunar eclipse, thl7 l1o/nga-sr *4ocbt2kpce6 e Moon, Earth, and Sun all lie on the same line, with the Earth between the Moon ats7/elg 4pbl 2-c ona6*rko1cnd the Sun. 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 is tran8h *tj2tao +dysported 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.t.(+j +.phq;ww-o cwwvpm3 ys , it just skims the surface of the Earth). What is the speed of the satellite? (The mean r.s;hyp+w+mjwqowpt - (c .3vwadius of the Earth is $6.38 \times 10^{6} \; m$.)

  A satellite is in a low circular orbit bql7fqu uwbofn+j1: o.31i m/about the Earth (i.e., it just skims the surface of the Earth). How long does it take to make one revolution around the:q 1ufimo73uf 1 bq /+bjow.nl 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 ipm*st9m nvft)p e)t+yvj1yk2z: 1 d 6observed to have a period of 89 min. What i2e1p:vt9)) +msn i p zk jtdm*6tvyf1ys the mass of the Earth? (The mean radius of the Earth is $6.38 \times 10^{6} \; m$.)

  Europa, a moon of Jupiter, has an orbital diameterzhf z kbaz. 28mp0+aes);rz6p 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 thq47 q w1ppbrw8e 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 nel)rgc semd v*7qo *ii/iu278early circular orbits. Moon A has orbital radius r, and moon B has orbital radius 4r. Moon A takes 20 days to c rcve*o)7e/qm gliui7d2si8*omplete one orbit. How long does it take moon B to complete an orbit?

  The planet Jupiter isq0s. r/;fqa vb(i-tkb $7.78 \times 10^{11} \; m$ 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. Wha upmj q6;yrx1p2i7+xst is the average dist s7;q2yp6xij xrum +1pance from Jupiter to the Sun? (The distance from the Earth to the Sun is $1.5 \times 10^{11} \; m$.)