Is it possible for an object movi2n soi -bkdq6c.odf8 0ng with a constant speed to accelerate? Explain.o cf6dk dq2.o 8-0snbi

  Consider a particle moving with constant speed such th8,rg4(r tn luhat its acceleration of constant magnitude is always perpendicular to grl(r ,8nuht4its velocity.

  An object moves in a circular path at a constant s2bktz2wj oo5ua 8d83g peed. Compare the direction of the object's velocitydoj28auow z2g 5bt 8k3 and acceleration vectors.

  When an object experiences uniform circular m,h:iexa9d brk+;h bv+m )m.sqotion, the direction of the acceledbkexqa m9+;hv i m. s,+:)bhrration is

  Consider a particle moving with constantsm3lc19:3 eysm owlx7ear : 5u speed such that its acceleration of constant magnitude is always perpendicular to its vwaxmssrc: oly31ml3: u ee795elocity.

  What type of acceleration does an object moving with constant speed i/o y/;wauntlh yg1:6 +symra0n a circular at g+h1m/w6y: onyy0l aur s;/path experience?

  What force is needed to make an obj+xn zxj3ay +ibb3a 0;nk a)g1oect move in a circle?

  When an object experiences uniform circular motion, the directizv 49ov)z het9on of the net force it 9oehzvv)z49 s

  A roller coaster car is on a track that forms a ci/1 :ycf /5m0cwcb*nfaxkjv /c rcular loop in the vertical plane. If the car ivka mc0fb/ c/:y*cw/f 1jnxc5s 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 apl j1m0n ij-2 a ua.pikn(2;bw circular loop (radius = r) in the vertical plan.1;naj (i0ppn- b 22ljimu wake. 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 div673 o:nprpg2xmuxbk k tv fo0s5d .9i2e then follows a semi-circular arc until it is going straight up. Just as the plane is at it2n9g uk m.otfix7dr6pb :k3o x0s52vps 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 owdeyxpg/zjw)i.-sdh *- + hh.sxub)* 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 aro5;s znfov danf6kcr c** y9uj9(old23und the same curve at half of the original speed. What is the ocfcay * o* sf92lr d3udv9;znj5(6kncentripetal 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-9. btqu i8homtcf2k+ constant speed v. Then it goes around a curve of radius 2r at speed 2v. What is the centrip 9mctko +8hqbutf2i- .etal 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 r n+awtc o3v2x3 *3+slleeu+ xof radius r with speed v. If the road is frictionless due to ice, the car can still negotiate the curve if the horizontal comuxw3tl2+3 e r *avol+n s+xc3eponent of the normal force on the car from the road is equal in magnitude to

  Two horizontal curves on a qe,8ph+mku ,.si p(ai 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 smaller radius curve is v. What is the safe speed on the larger radius curi,i(ks pa8e.qhm,u+ p ve?

  The banking angle in a turn on the Olymp +1y5pn ,kr btvfbx:*mic bobsled track is not constant, but incrf+ : vytkp*bnb, xrm15eases upward from the horizontal. 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 object moving around a circular e12tn2, x:tofw(yqmapath to have both centripetal and tangenti(mt , eox1 nfwta:22qyal acceleration?

  The gravitational force bfw*cp ,dbh,8d cx fb(zn5 mn x)leh)*0etween two objects is proportional to

  The gravitational force between two oxy gzoo,8 8qflkjy jt.;7da8/bjects is inversely proportional to

  Two objects attract fldtdj-k10/t /4/gb9u oviuy each other gravitationally. If the distance between their centers is cut in half, the gravitational forcfdt-uyglb ijo4t /v k//u910de

  Two objects, with mas-d9ruu) lz6(q lpemj9ses $m_{1}$ 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 masserbp3,af.rxgoy i: 5/is $m_{1}$ 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 gravqqp3yhkut1 8+ye5/2 ua xa0hvitation.

  Compared to its mass on the Eaz xe;n5qo/wlce2 p5hci;)ap +rth, the mass of an object on the Moon is

  The acceleration of gravity on the Moon is one-siolz,-fs d0ci 2zlx5 w0j 4m( *iwfww7sxth what it is on Earth. An object(-4wwwz 7ifs f 52 oxlzdlc*s,jmi0w0 of mass
72 kg is taken to the Moon. What is its mass there?

  As a rocket moves away from the Earth's surjws 1.v3gln: kface, the rocket's weight

  A spaceship is traveling to the Moon. At what point is it beyond the pull of E4us::ra7w34c sber iu+0pt r gagpc+40e r u:asi s:urtr3 w74brth's gravity?

  Suppose a satellite were orbiting tdo6 2q*9ce uikzrio.4 he Earth just above the surface. What is its centr rzo6ei24uo *q9ick.d ipetal acceleration?

  A hypothetical planet has a mass of half that of the Earth and a d* 1f *xhi)uhjradius of twice that of the Earth. What is the acceleration due to grav xh*i)ujfh*1dity on the planet in terms of g, the acceleration due to gravity at the Earth?

  The acceleration of gravity on the Moon is o9lj/ ci7,rhr5o32em)xh 7fjq4 5r cjni+kmqnne-sixth what it is on Earth. The radius of the Moon is one-fourth thmi h njr) 3cejl54,o7h/r2fxqm j7 +r5qk i9ncat 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 tq4 t lnh 5 efmq,g0idm6b9v6t( *jj2mhhe radius of planet A. If planet A has mass m, whm5emh6fhg4tti 2dl ,* q( vj6mbqn90jat is the mass of planet B?

  Two planets have the sabc *;ia8xmvihvkdca:h0 9 j 0.me surface gravity, but planet B has twice the mass of pla icxv 0mk;cai0jdhv:9 ba*8h. net 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) ab u56scm)w9hjhout a spherical planet (mass M). Which expressiojs9h)m cw hu65n gives this satellite's orbital velocity?

  Satellite A has twice the mass of satellite B, and rotatec3xxdk)1k:z rtn ;sz4ii n5o4s in the same orbit. Compare the tw;k4 r4s3:o5x)cdn ii1nz ktx zo satellite's speeds.

  A person is standing on a scale in an elevator accelerating0tmm:+e,oa a3,zxsfp downward. Compare the , a maf:xpo+,30mzst ereading on the scale to the person's true weight.

  Who was the first person to realize that the planets move in elliptical pat dc/e 1 4pv0vu9ikmiy0l gbxfg-c-) 4bhs around the S c vvyclf/4)9mbip 1uge4b-xd g00k-i un?

  The speed of Halley's Comet, while traveling in 4.u30n nagbth its elliptical orbit around the Sun,hg3 bunt.4 an0

  Let the average orbital radius of a planet be R. Let tha6k. jj/ d zumlvu7*eu;+xqh 8e orbital period be T. What quantity is constant for all planets orbit7u 6x vzj ;+u k/*jdlqeau.8hming the Sun?

  A planet is discovered 5ry-tr lz1 ht5;-xnq h:8vxjdto 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, whd1; hxzvttn 8-xhyq lj5 -r:5rat 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 one vzf tj) 0 vfu9*ywyb7/ eh lcd hp3-,4k,a5dsp"astronomical unit" (AU). An asteroid orbits the Sun in one-third ofy 4z0u,dpd/pa, s)fl9-jbwh 7*eh fcytv 3k v5 a year. What is the asteroid's average distance from the Sun?

State Kepler's laws.yfvy9nlcvb 40-pnl/w+ 1zo 4vhree ,uq7. 1 cy

  List the four fundameyl, 8l x e3p.y:1awu6qlugg*cf rv -u;ntal forces in nature.

  An object moves with a cyg82925creuhyi hi(r onstant speed of 30 m/s on a circular track of radius 150 m. ri8er2 2h9 5(cgiyuyhWhat is the acceleration of the object?

  The maximum speed around a level curve is 30.0 km/h. What is the w8fwte*4rco mx(jo3j;pl )c 7maximum speed a78l;3fw)c( wrjpoom *exj4ct round a curve with twice the radius? (Assume all other factors remain unchanged.)

  What is the centripetal acceleratioawo p1r h2cer2gdz21*f2woq: n of a point on the perimeter of a bicycle wheel of diameterw2w:o crqge2do* 2r1hf2z a1p 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 the axis. Wpv td3j;4.clb hat is thelbjcd.3; pv t4 centripetal acceleration?

  How many revolutions per minute must a circupsz(rzlzw/fo 9tb76oz mes,(g :k (s) lar, rotating space station of radius 1000 m rotate to pro mzw ts(:f,(pszos e6l)/go9zb7( krzduce an artificial gravity of $9.80 \; m/s^2$?

  A motorcycle has a mass of 250 kg. It goes around a 13.7 m rln/79tyx sr2 s2cwk1radius turn at 96.5 km/h. 2lssxwyr tr/1792 cnk What is the centripetal force on the motorcycle?

  A 0.50-kg mass is at7j5srmge y*yf5 hla** tached to the end of a 1.0-m string. The system is whirled in a horizontal circular path. If the maximum tension that the string can withstand is 350 N. What is the maximum speed of the mass if the string is notgre5jsy*am*l57*h f y to break?

  A stone, of mass m, is attached to a stronu7:m4m(7dg gl7j nct f6sm yv;g string and 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'smnmg7 7 y7fsl: m4u6t(vc;djg speed at this point is given by

  A stone, of mass m, is attached to a strong string and whd r :2xf13rk-ot;o*n7 pzsor yirled in a vertical circle of radius r. At the exact bottom of the path the tension in the string is 3 ti1 otrd:y*;z2nr r 7x s-fopo3kmes the stone's weight. The stone's speed at this point is given by

  A jet plane flying 600 m/s experiences angn n,a, ass7s-mr ;+qj acceleration of 4g when pulling out of the dive. What is the radius of curvature of the loop in which the plane is flqg+;s,7a, jn rnsasm-ying?

  A pilot makes an outside vertical loop (in which the center of the loop is ben: n/ym22q/ahiofh. n yeath him) of radius 3200 m. At the top of his looh/.om22n h n/fy:qy aip 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 +f whfe xg 492oqv.e/dis the minimum radius of curvatur+o 4g/fevx2 fqewh.d9e 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 witq/ otgvu7:/ac/ q tj5th the tires on the verge of slipping. How fast can this cacqu/a5vtgq/t 7/ :tojr 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 spe1bq4v72prx dk ed of 20 m/s. The centripetal force provided by frictk vx41r72dp bqion 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 1,c :j j,m yp:,no r1c(0lgl;qwslfj.n4 m/s. What must be the minimum coefficil,jwsq rp oc 1,nn:;lymcf.jl :, 0gj(ent of friction between the tires and the road for the car to make the turn?

  A car is moving with a constant speed v around a level curve. The coef-r9/f) cjthyi ficient of friction between the t jtrc)f/y -ih9ires and the road is 0.40. What is the minimum radius of the curve if the car is to stay on the road?

  What minimum banking angle is required for an Olympic bobslemf9bb f+8 e)cb jd+r+hd to negotiate a 100-m 9 bdbber)+hc+m+f8 fjradius turn at 35 m/s without skidding? (Ignore friction.)

  A horizontal curve on a bobsled run is bc+ y0-6cfhjwoanked 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, bagns3: /3t 3nv5tmjtny+s 7rjunked at an angle of $45^{\circ}$, may be safely negotiated at a speed of

  A curve of radius 80 m is banked at am *.p x88wojk(riyap/, ph7o-afmnit3f 64v $45^{\circ}$. 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 horizh79/pd td,2defgr ,haontal circle of radius 0.5hrf 9 gddetp,7a/,2hd00
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 un )q( hdzq-dwy+iform rate to a speedhy) -wq+dqd( z of 45 m/s in 15 s, moving on a 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 consivli 5bj(opegu*3 qf15sts 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 7cn)gvg9 hn4zxj k(l+(0-kg person standing on the Earth, due to the Moon? The h+ vc(ngk(g 49 xjl)nzmass 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. If (ro 3vpkz 5v)i-a.orm the masses are moved to half of their initial distance, what is the gravitational attracav3 po.)5(-kvrrizo mtive force?

  For a spacecraft going from thb0g) 0c6zxxeqe Earth toward the Sun, at what distance from the Earth will )zeg 060 qcxxbthe gravitational forces due to the Sun and 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 is amj* *rxth22 t$7.4 \times 10^{22} \; kg$ 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 to b bb0:.l+kfv 8lgfqh5the radius of the Earth. What is her acceleration due to gravity? qh: fg.f5bvlbkl8b+ 0

  The radius of the Earth is R. At whapth39 xadp +4t) -sw l-matu:pt distance above the Earth's surface will the acceleratio4 lhs:t3d)p tpaa w-ut9xmp+-n of gravity be $4.9 \; m/s^2$?

  A satellite encircles Mars at a dis/eyv sds.d*;4 ;rd d/;scvuty0 be: vatance above its surface equal to 3 times the radius of Mars. The acceleration of gravity of the satellite, as co0 e;;.s vdaytydsv / ;*r/:udd4ev csbmpared to the acceleration of gravity on the surface of Mars, is

  At a distance of 14000 km from some planet's center, the acceleration of gravitz26mkv0 pfd h,.piv-jy is h pf0.6j v 2kvpiz,-dm$32 \; m/s^2$. 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 haso* (9sn2xl g, rni6v3 jv/5ij(ovtywy radius r. If the object is raised to a height of 3r above the Earth's surface, what is its weighnwy 9 xvvt(rli ,/25j*6o (jsognvi3yt?

  By how many newtons does the weight of a 1006ctl/ a,k ik5j0sel+v9f8 jug-kg person change when he goes from sea level to an altitude of 5000 m? (The mean radius o56 /ligk lcs,9v +kuaef8j0tj f the Earth is $6.38 \times 10^{6} \; m$.)

  The Earth has radius r. A satellite of mass 100 kg is at a po-vz 6gd7m-6)q;w xlj 9sv eefxint 3r above the Earth's sur 7ev6xefd6;-jml)w-xg vq9s z face. What is the satellite's weight?

  A spherically symmetric planet iz4t;rvbkdy vq ah,lu/0 /5g, has four times the Earth's mass and twice its radius. If a jar of pean,vtyu zr;qhv/ia g, 4l0d5 bk/ut 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, Earth, and Sun all lie on the same 2547ejfakw bh line, with b e 5w27jhfa4kthe Earth between the 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;okx g 9c9bj92ty yqe,u vcd25 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 cirh k/) mjwkt; 2lsmm.-rcular orbit about the Earth (i.e., it just skims the surface of the Earth). What is the speed of the /.mrw khl) m;j-ktm2s satellite? (The 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 skim);jwq o/ez r.b--yt5s)g q3er6pmw o ds the surface of the Earth). How long does it take to make one revolution around the Earth? (The mean oj6 tdbsw5r-3/.) yw pm;e-oqg qzer)radius of the Earth is $6.38 \times 10^{6} \; m$.)

  A satellite is in circul-3grnf iq)s01 n( vw xqh/tam u,twp)/ar orbit 230 km above the surface of the Earth. It is observ-g30 wph i1fwt(m/n q )tvsn,/ uqa)rxed 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 an orbital diams. dvrb;2 +w.mobutf (eter 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 t r5yv dk t,sxe;tz175zhe 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 necpxz 9z t/x4bpv zs8a4sa 181larly circular orbits. Moon A has orbital radius r, and moon B has orbital radius 4r. Moon A takes 20 days to compv/8zcs94sxlp41z b xa1 p8a ztlete one orbit. How long does it take moon B to complete an orbit?

  The planet Jupiter i*hog+ 51w.nwb+vtsf ss $7.78 \times 10^{11} \; m$ 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 b5xso wfu1r9*hrh1q d71 yqv.once. What is the average distance frqbv9 dsh.xy1w175 rquf o1rh *om Jupiter to the Sun? (The distance from the Earth to the Sun is $1.5 \times 10^{11} \; m$.)