Is it possible for an object movii7w xvj2k-fbxtj )0(mng with a constant speed to accelerate? Explainkjw7 iv-fxj2(b) xtm0.

  Consider a particle moving with constant speed such thabkad y7 dl58g+-u-)d xzh(7 cil1dupqt its acceleration of constant mah- abz7p u5dkg+- q8l d7ddil)uyc(x1gnitude is always perpendicular to its velocity.

  An object moves in a circular path at a constagnf2 5ovmu3r -nt speed. Compare the direction of the object's velocity and acvo-2r fgn 3m5uceleration vectors.

  When an object experiences uniform circula9qjikg+gmk) 1 r motion, the direction of the accelerat )9gikm qjk+g1ion is

  Consider a particle moving wit5mlnva hvx,va;2xdv4jjxtkk ,-h-5 ; h constant speed such that its acceleration of constant magnitude is always perpendicular to its veloci -m4nvkh;2xl tvh,5kx-v,a adj5;x jvty.

  What type of acceleration does an object moving with constant sxl;9 bw)ujh-zpeed in a circular path experi ;w)b -zlxhu9jence?

  What force is needed to make hm 65hd.cobxzsd 2 qwd9c1:j3an object move in a circle?

  When an object experiences uniform circular motion, the direction of tp+bd3t :d.37abkinxskk)0 p she net for)3.d7xa0ipbk+ dsb tnspk :3kce is

  A roller coaster car is on a track that forms a circular lnyovrr5 cc8td: x6z u70tby60 2cq7xvoop 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 acceo0c6n:zu y5q76rcb8 v y2xt 7tcd0rvxleration at this point?

  A roller coaster car (mass = M) is on a track that forms a cog5ywe ng4v 8qr)j 8-einfw:, - fi:qkircular loop (radius = r) in the vertical plagyr gnwk n -i8j4ew:fv -q,5oqi)fe8:ne. 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-circul:- p;3cy txcuqnna)l*ar arc until it is going straight upxqncn-;t lc y :3*)aup. Just as the plane is at 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 curve o2 hqirvfip gxk/i/:3 jw6+3pv rr0w.q f 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 goes aigj) ,r+e7ot hround the same curve at half of the origo, 7i+jtg)rehinal speed. What is the centripetal 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 consta/up-,m6f m4 eziis6x jnt 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, comjz e6pf,s-xim4i6 /u mpared to the first?

  A car of mass m goes around a banked cur*dnh96)e ms obve of radius r with speed v. If the road is frictionless due to ice, the car can still ne9 )6*h bnsdeomgotiate the curve if the horizontal component of the normal force on the car from the road is equal in magnitude to

  Two horizontal curves on a bobsled run are banked at the sam/.rrclx9hcq l vm3.d-e angle, but one has twice the radius of the other. The safe speed (no friction needed /cl3dlmx.rcv .9- hrq 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 not constant, yy5 ngvo3np)*z(r dz,but increases upward from the horizontal. Coming around a turn, the bobsled team will intentionally "clim)ynv 5z(y*zgp,r dn 3ob the wall," then go lower coming out of the turn. Why do they do this?

  Is it possible for an object moving around a circular path to have both cep bt84a. jum0+tnb8yn: t:wqentripetal and tangential accelerati m 48ja.e0bbt:8ntw tp:quyn+on?

  The gravitational force betwe,a5voq o. az,x95yg7lgkz3 phen two objects is proportional to

  The gravitational force between two objects is inverc eh9b/rhf,d. sely proportional to

  Two objects attract each other gravitationally. If the distance betwekpljgc )f 0.aws m(,uo7ih (n8en their centers is cut in half, the gravitatiosch. ukln fm g87w(0pa),oij(nal force

  Two objects, with masses ztdn6;azf* otn1sz0 ;$m_{1}$ 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 mas4g( u/oh4opcj* 1r jihses $m_{1}$ 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 gravita b7pbx ym6fq(51yikd-tion.

  Compared to its mass on the Earth, the mass o7r0s5c-eg kjtb (7 isnf an object on the Moon is

  The acceleration of gravity on the Moon is one-sixth what it is on Ea.yt tijq) (,s atg9k7lrfeqbc i/i-+1rth. An objea i, yt b7si- qt(/f+l1 ctj9eqr.gk)ict of mass
72 kg is taken to the Moon. What is its mass there?

  As a rocket moves away from the Earth's surface, the rocket'so+ec55.w uwwvxhdd (dc20j s6 weight

  A spaceship is traveling to the Moon-yeql d: k7b3o11ep0;4 mn9fvqw fnmv. At what point is it beyond the pull of Eare9fmf4k-d0w q nvyon 1;lp3b 7qe1 mv:th's gravity?

  Suppose a satellite were orbiting the Earth x6qe nj8*e r5ejust above the surface. What is its centrrxn6ejq e8*5e ipetal acceleration?

  A hypothetical planet has a mass of half that of the Earth and a radiusz 2j-0* rn9:j e/ sthy3esuka;epgou+ of twice that of the Ea +-ae 2hujo r 9g /stun3zsep:ye*0;kjrth. 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 Moonigawhcqeic-g 934 ho :sz .d5/ is one-sixth what it is on Earth. The radius of the Moon is one-fourth that of the Earth. What is the-ozs5dc3a./ggi49iq: h cewh Moon's mass compared to the Earth's?

  Two planets have the same surface gravity, but planet B has twice thwmev). 96rnp pyqi v57e radius of planet A. If planet A has mass m, what is the mass v9i5 qppm n 6w.y7erv)of planet B?

  Two planets have the same surface gravity, bu 7c io:fxexo)et57f zyu, ,yyy)d 4 pnyd--lj8t planet B has twice the mass of planet )4-)cyo8i dyly,5f x 7xpznyueef y:jo-t7d,A. If planet A has radius r, what is the radius of planet B?

  Consider a small satellite moving in a circular orbit (radius r) about mqju 1 krp6t9yl5se81.* z uzha spherical plarsz puu8l*91e.m tzhj1k56y qnet (mass M). Which expression gives this satellite's orbital velocity?

  Satellite A has twice the mass of satellite B, and rotates in the same orb f7ig e dozf1o::lu6gk ,-rjk.it. Compare the two satellite's speedfjg oe-,rf1ig: olu. z:k6d7k s.

  A person is standing on a scale in an elevatom5e fac-f9sf, r accelerating downward. Compare the reading on the e fs9, -ffamc5scale to the person's true weight.

  Who was the first persl/r fjxx.6+btu *r r39c*bh seon to realize that the planets move in elliptical paths aroue6+fr.rx*j3b sublc*t9hr/ xnd the Sun?

  The speed of Halley's Comet, while traveling in its elliptical orbit around the 59 f,qu4xul (uwka /4im)rj.a8a qqoj Suu54 q)aq.f/wxr alojm(q4i j ka8u ,9un,

  Let the average orbital radius of a p,q;pow7jk th 8lanet be R. Let the orbital period be T. What quantity is constant for8oj;q, hp 7twk all planets orbiting the Sun?

  A planet is discovered to orbit around a star in the galaxy Andromeda, withjz96hr0*x l k az,a3sh the same orbital diameter as the Earth around our Sun. If that star has 4 times ,k39jl*h0ha6srzxza 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 Eaunnn r4/:m;wsrth to the Sun is defined as one "astronomical unit" (AU). An asteroid orbits the Sun in one-thirwn rn/nsm ;4u:d of a year. What is the asteroid's average distance from the Sun?

State Kepler's laws.vv bok mi5 a,ycd;:nmqf;x 5+2

  List the four fundamental forcezj ,md6ai7k 8pjacq 4:aix5o+s in nature.

  An object moves with a constant speed of 30 m/s on a circular tra -)sql+xl(tc sq sqx;t6-pb 6jck of radius 150 m. What is tbjts+-qt(; xslls-qx) 66 p cqhe acceleration of the object?

  The maximum speed around a level curve is 30.0 km/h. Whatb;)l: bhax 3yaphih2 ; is the maximum speed aroun3i:yp2hxaa) lhbhb ;; d a curve with twice the radius? (Assume all other factors remain unchanged.)

  What is the centripetal acceleration of a point on the perimeter of a bicycle 8-h 3x)2z 4nfazofgeucv ina*dd8 1i8wheel of diameter 70 cm when the bike is moving 8ffxzaz 84nai ni*2eoud h8cg d)-3v18.0 m/s?

  A point on a wheel rotating at 5.00 rev/s is located 0.200 m fphuyft y.4mdv( h(0j)w y-*nprjz : v3rom the axis. What wy) y( mjuhh3 *t-(0:fp vnjd4ryz. pvis the centripetal acceleration?

  How many revolutions per minute must a/ wuyq6v9h; 0ngsvl- g circular, rotating space station of radius 100 0s9l6vu- vnw/ygghq; 0 m rotate to produce an artificial gravity of $9.80 \; m/s^2$?

  A motorcycle has a mass of 250 kg. It goes around a m *fpq vu48de.,xozd*13.7 m radius turn at 96.5 km/h. What is the centrip ve*qfp*4.odzx u, m8detal force on the motorcycle?

  A 0.50-kg mass is attached toris3tz i 5c6f)fy 2v,o the end of a 1.0-m string. The system is whirled in a horizontal circular path. oyzf),sti 56 r2c3ivf If the maximum 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 attacheg ys t7x-at nkmx;8++pd to a strong string and whirled in a vertical circle of radius r. At the exac + xk8 s-7xa;tgtpnmy+t top 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 stone, of mass m, is attached to a strong strzljlp- e mwwgsfp*2 g*f59:y+ ing and whirled in a vertical circle of radius r. At the exact bottom of the path the tension in the string is 3 times the stone's weight. The stone's speed at ts*p w*5+:9gfw gl jy mp-ez2lfhis point is given by

  A jet plane flying 600 m/s experiences an acceleration of 4g when pulling outg(u d 67q+myp ec0rk/*sutg*:pa,zfn of the dive. What is the radius om+*g 6:r(ydkpuuc 0nf,ps/aeg t7*zqf curvature of the loop in which the plane is flying?

  A pilot makes an outside vertical loop (m56u1p 2q suzg g66vfnin which 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 is 1p52m n66gv6usgqz fuhe going?

  The maximum force a pilot can stand is about seven times h85eg5+ vnfz /7gbvb( (bxz nswis weight. What is the minimum radius of curvature that a jet plane's pilot, pulling out of a vertical dive, can toleb / n58wsv(geb7fvzxngbz5 (+rate at a speed of 250 m/s?

  A car traveling 20 m/s rounds an 80-m radius horizontal jxxxj,g8;ov 5curve with the tires on the verge of slipping. How fast can this car round a second curve of radius 320 m? (Assume the samejx ;8,vojx g5x 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 of 2-o *bhyc;vqe,v/oon .1c 1o jv0 m/s. The centripetal force provided by yvooo nev*1b-,c;oq.1 vh /c jfriction 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 n5 nji41ikqj/ f2k )jpa speed of 14 m/s. What must be the minimum coefficient of fp5 q) k4ni kji1jnjf/2riction between the tires and the road for the car to make the turn?

  A car is moving with a constant speed v arouc2 5uk j/fs-6qwin. wund 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 car2 w-.kuqi/swnjf 65uc is to stay on the road?

  What minimum banking angle is required fo3- uu 5hpxfwsktyab3: y,q(+zg1 n*jm5gnpy (r an Olympic bobsled to negotiate a 100-m s(a5tkzn jbgx3yp1,fhw3:m-n 5q +uyuy* g(p radius turn at 35 m/s without skidding? (Ignore friction.)

  A horizontal curve on a bobsled run is banked quq/s5 qg65bp 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, bxgmhsd m:c 3ay9 co8 19c7iz,;arc bm3anked at an angle of $45^{\circ}$, may be safely negotiated at a speed of

  A curve of radius 80 m is baobal* hde :do)r4u)*nnked 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 evwaj4eiax,8tl ,-1oh0* e rbrevolving uniformly in a horizontal circaox w*trv b e,8e1 0ija,4l-ehle of radius 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 qivo5+)rooa -at a uniform rate to a speed of 45 m/s in 15 s, moving on a circular track of radius 500 m. (only fill in nu )oar ioq5vo+-merical 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 cons i(nb gu7hoqi,-nb7blltim1k( +;v.( s lsch9ists 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-:2pof69hnq i5ee5syenc op.pt 7 w4g on the Earth, due to the Moon? Te6:5.5pphp2 s egft -4oncw io7eqy9 nhe 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 masses is F. I - jlt4o;.yv.gk *ah 8or37suszgx0iff the masses are moved to half of their initial dista shu-j osog7tal yfv.0;x .izgr84*k3nce, what is the gravitational attractive force?

  For a spacecraft going from the Earth toward the Sun, at what distance from thy9; 3rbqr ef+ze Earth will the gravitational forces due to the Sun and the Earth canz3 ;yr9frq+eb cel?
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 isp ak-5hq 5ovq( $7.4 \times 10^{22} \; kg$ 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 ab85s kc: +q9owet cnw5gldwl,*r ls 1*vove the Earth equal to the radius of the Earth. What is her acceleration:wn5 5 wrc9c w+ llsovqgk 18setdl,** due to gravity?

  The radius of the Earth isf. - j:t.iqwtt R. At what distance above the Earth's surface will the acceleration of i t wtf:..jqt-gravity be $4.9 \; m/s^2$?

  A satellite encircles Mars at a distance above its surface equa .)z1orw r;xe*jm d4pw d22kyal to 3 times the radius of Mars. The acceleration of gravity odm;w4 r2epr2 k*j)a.x dwyzo1f the satellite, as compared to the acceleration of gravity on the surface of Mars, is

  At a distance of 14000 km from soau.s/)cgir. ug-s )bmme planet's center, the acceleration of gravity ismgsbu-.g) /usa.c)i r $32 \; m/s^2$. 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 ho5 *(f p9raflmas radius r. If the object is raised to a height of 3r above t(l 5f9 pofa*mrhe Earth's surface, what is its weight?

  By how many newtons does the weight of a 100-kg pd p ;lz4 t9x74li/lf 53 f:goud0bvjpeerson change when he goes from sea level toj5pie: 3bl;uf97 0ftv p/l ddo4lg zx4 an altitude of 5000 m? (The mean radius of the Earth is $6.38 \times 10^{6} \; m$.)

  The Earth has radius r. A satellite of mass 100 kg is at 9fvlwt6e03 x)gr-aj j urihz)w2*k1 ia point 3r above the Earth's fuww e9xrj0j1a tr)v) z-hgil* 6k32 isurface. What is the satellite's weight?

  A spherically symmetric planetu l9:3hritblaa78a /puxns.. has four times the Earth's mass and twice its radius. If a jar of peanut butter weighs 12 N on the surface of a 3nbs ara.8 puhul7i.:l/x9tthe Earth, how much would it weigh on the surface of this planet?

  During a lunar eclipse, the Moon, Earth, : h*/zcguq-bv and Sun all lie on the same line, with the Earth between ubc/v q :*z-hgthe Moon and 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 transported to the Moo7- 225*v wdrd6wnjo4pkqf pnd n.
(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., it just skqugi9 xp a(po/ t49nn*ims the surface of the Earth). What is the speed of the satellite? (Theq (4to u9 ax/ng*pp9in mean radius 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 the c.f1,-2jiw pm8z qamnsurface of the Earth). How long does it tak.-m81 cipnfmazqwj, 2 e 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 kxekn)k5e .1fahx9+:w5o me 1 oih6l borbit 230 km above the surface of the Earth. It is observed to have a period of 89 min. What is the mass of the Earth? (Thlik:kb .a9wee oxhxh e)fk6+5mn11o5 e mean radius of the Earth is $6.38 \times 10^{6} \; m$.)

  Europa, a moon of Jupit * 5vvd :c*vlkbnz.iz3er, has 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 Jupiter o-tb:5 ewcv,jr rbits 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 orbitalj83 +ny/;q0ln(n hicpbv.e ac radius r, and moon B has orbital radius 4r. Moon A takes 20 days to complete ob;+3n8c c/iv.j0( n lpenh yqane orbit. How long does it take moon B to complete an orbit?

  The planet Jupiter is 6z, ttle+zox ;$7.78 \times 10^{11} \; m$ 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 orbitxob x bog*+269ll6azp the Sun once. What is the average distance from J6ox9pbzl2x al o*6gb+ upiter to the Sun? (The distance from the Earth to the Sun is $1.5 \times 10^{11} \; m$.)