Is it possible for an object moving with a constant speed to;vz qo +y-si/k accelerate? Explaio/+k-z; s vyiqn.

  Consider a particle moving with constant speed such that its accele;l onicuar/+ rvso0(/ration of cons/u;ran s0o( +lcio/ rvtant magnitude is always perpendicular to its velocity.

  An object moves in a circular path dz.s inj+tmj.7gj,y9- 1 sqghat a constant speed. Compare the direction of the obj.1y jtd ,-jq 7jigzn+m.shs9gect's velocity and acceleration vectors.

  When an object experiences uniform :ge9apg d.z , dmq2gi-circular motion, the direction of the acceleradeg2z: -g.,9apgmiq dtion is

  Consider a particle moving with constant s: n6jtcmlm:-vos pa(arh 2m bh0i1)f9peed such that its acceleration of consta(l:0anop6)v9m :cfj1m2rtbis h ahm- nt magnitude is always perpendicular to its velocity.

  What type of acceleration d zx0p1qns2b* zoes an object moving with constant speed in a circular path experi1q0zbnz s2xp*ence?

  What force is needed to make an o0o*ddx-2n gb object move in a circle?

  When an object experiences uniform circular motion, the direction of the net fogrlc2f x4gp9 9rcrcgpf9gx l942e is

  A roller coaster car is onm a:n;1 frt/cv2eew8m a track that forms a circular loop in the vertical plane. If the car is to just maintain contact with track at the top of the loop2;cre nae/ 1 wv:fm8tm, what is the minimum value for its centripetal acceleration at this point?

  A roller coaster car (mass = M) is on a trackm50lv ;zgor o46qd8aw that forms a circular loop (radius = r) in the vertical plane. If 4amol6zq 0vwgdr58o ;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-circularrdyb(n/tz g i;,b;3gk.tw y; s arc until it is going straight up. Just as the plane is at its lowest point, thy/i. (gsg ,z;;;k y3b rtwdnbte 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 oz5n3 c9/7s0 syqeekhfc6 p.p $r$ 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.q+ +vlfv o6 lja,w(h9z 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, comparedfov+lqvwj (h+ 9,6 lza to the first time?

  A car goes around a curve zm yyr5t:q 3a6yn :(+vrtk ,czof radius r at a constant speed v. Then it goes around a curve of radius 2r at speed 2v. yqrrtk5+ , v:3 azmyynct:z6(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 uv4k.+-ifa k cqg)j.jof radius r with speed v. If the road is frictionless due to ice, gfk . q4a.k+vcjju- )ithe car can still negotiate 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 same anglej sl.xu+x 0vp- uw-nf0, but one has twice the radius of the other. The safe speed (no friction needep+sjln 0x .ux-f -wuv0d 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, but inae5k 06m flf4bcreases upward from the horizontal. Coming around a turn, the bobsled team will intentionak46emffbl5 0 ally "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 c) f .6dgfw6rxyyq)3eidg.u d(:*es hmjjq,5xircular path to have both centripetaleje):)myfy* wifgg h 6q ,.56drs3x dxuqdj.( and tangential acceleration?

  The gravitational force between two objects is proportional t t*4h31l-fu d zegbd.po

  The gravitational force between two objects is inversely proportional 5bzzba28y8ic to

  Two objects attract each other gravitationally. If the distance b3n/ggi1o tv4 xetween their centerst/4xo gni3gv 1 is cut in half, the gravitational force

  Two objects, with masseunt5:p4xk z i:7 (dvzus $m_{1}$ 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 massesx3w9 ,.pym44a 5bqwcm(njb ot $m_{1}$ 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 gravitatiyuoa8m.( zcjetc( c) *on.

  Compared to its mass on the Earthn7w 9byy7+e(e7wfb4 n ayn1no, the mass of an object on the Moon is

  The acceleration of gravity on the Moon is oneym1bk fp d1m0mj/hn*n d 4ufoj ,(y2w5-sixth what it is on Earth. An object o 4y*/hjp, (oy0kdfd b n nmf51wmumj12f 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's wei(h vdnk :nyhe7.n:xj3ght

  A spaceship is traveling to the Moon. At what point is mm4(nz(llc4 :w1 93u dnaitlbit beyond the pull of Earn1i4l4m:( dua3n9 z(lb wltcm th's gravity?

  Suppose a satellite were orbiting the Earth just above the surface. jbsa+:q4ob -n(/arr /o g :bz5(*bgdrvz-hlfWhat is its centripetal ac - raz4nr5a *zh/r:qbvo +(b(fj :od/sgg-lbbceleration?

  A hypothetical planet has a mazp(z9 str;z,1 (oe.miq 5rndxss of half that of the Earth and a radius of twice that of the Earth. What is the acceleration due to gravity on the,dz(;mepi91r . 5z z(otnsxqr 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 7)g vdtx*2kegis on Earth. The radius of the Moon is one-fourth that of the Earth. What is the Moon's mass compared to theg7k*g)d xe2tv Earth's?

  Two planets have the same surface gravity, but planet4bjh zopi-*z3fvvwo s1)n(5o B has twice the radius of planet A. If planet A has mass m, what is the mass wo b)(vf3j5*v oni- z4ho1 zpsof planet B?

  Two planets have the same surface gravity, but ut4jnlu*p-o *planet B has twice the mass of planet A. If planet A has radius r, what is the radius of planettu lp n-juo4** B?

  Consider a small satellite moving in a circular orbit (radius r) about a spherydl5x;s /nbg9ical planet (mass M)dny 9l5x b/s;g. Which expression gives this satellite's orbital velocity?

  Satellite A has twice the mass of satellite B, and rotates in vo8/aqyl z/2 *dn/z acthe same orbit. Compare tyc//lzno z8ad/ 2*qav he two satellite's speeds.

  A person is standing on a scale i9zd+3cpe au.x*0k uypn an elevator accelerating downward. Compare the reading on the scale to the person's true weigek*0 3px9c.+uu apdzy ht.

  Who was the first person to realize that the planets qp 4303q x* djccl6eiyj 5.skj;vob8mmove in elliptical paths around ikjjj cdse3y;4 58qpml6oq x 30b*.vcthe Sun?

  The speed of Halley's Comet, +r; 6*yy+(t oohagzxnzbz v71while traveling in its elliptical orbit around the S z+h *+6 nbgxr(ozo y7;azyv1tun,

  Let the average orbital radius of a planet be R. Let the orbital period be T. uj0gx h*s, d1;;kq baymjp+2lWhat quantity is constant for all planets orbiting the Su b;jkjxd;1uhqm+ *aps2 0 ,gyln?

  A planet is discovered to orbit around a s+yf)gunqww j o 1z(;*qr.j6 kjtar in the galaxy Andromeda, with the same orw*qun1+(q;j r f )zjkwy.og 6jbital diameter as the 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 one +g0ii;:80,mhsilu /yauczw/h l gz2y "astronomical unit" (AU). An asteroid orbits the Sun in one-third of a year. What is the asteroid's averag0uuiws m+ cl/g20z /gyhay;izi h,:8le distance from the Sun?

State Kepler's laws./v ;1,ojfecp a

  List the four fundamental forces in243z x sk j(5*v9ep5 wxjupmlf nature.

  An object moves with a constant speed of 30 m/s on a circular tl6xl 1u*s /h4mucam7jrack of radius 150 m. What is the acceleration of the c*l7 4uux6/j lhasm1mobject?

  The maximum speed around a level curve is 30.0 km/h. What is tc3r6 e2 mu4mephe maximum speed around a eum2c p63m4r ecurve with twice the radius? (Assume all other factors remain unchanged.)

  What is the centripetal acceleration of a point on the perimeter of a bicycle 4,px7 h9ay b9qvxj( nkrh ggu :f)z++lwheel of diameter 70 cm when the bike4,:jux+nz v) gyfpr l9 b+g7k h9(qxah is moving 8.0 m/s?

  A point on a wheel rotating at 5.00 rev/s is located 0.*wrc,x ut e46m200 m from the axis. Whaxmew*,4 6trcut is the centripetal acceleration?

  How many revolutions per minute must a circular, rotating space station of-8z l-ik q7w )tozja)q radius 1000 m rota)-ztw 7zoi q8ql-)j akte to produce an artificial gravity of $9.80 \; m/s^2$?

  A motorcycle has a mass of 250 kg. It goes aroagd,+l9 yl kjkwlpy6. vx 98+jixs78o ,u qi+zund a 13.7 m radius turn at 96.5 km/h. What is the centripetka,pud .wx+x8gs7z l j9y +9, io+i8ykllj6v qal force on the motorcycle?

  A 0.50-kg mass is attached to the end of2 7w.;wq g3oi8ck zasj a 1.0-m string. The system is whirled in a horizontal circular path. If the maximum tension that the string csgoki a3wwj.2z q78; 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 my2- tjb94ncda strong 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's speed at this poi-mjycnd4b29t nt is given by

  A stone, of mass m, is attached to a strong string and wh: ehaqvotik *36l5av) jt.c5di3fsu 5irled in a vertical circle of radius r. At the exact bottom of the path t tvhkqc:d3li aea.ui3t)s 5f5*o5 6jvhe 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 accelergqi4vwn (uf9gki w( i558aey o, kkh53ation of 4g when pulling out of the g5uhw f aoi i5k4v5 e3qi,kk(ny(8g9wdive. What is the radius of curvature of the loop in which the plane is flying?

  A pilot makes an outsicp ,pt3 s0*,skjg;zt((v k ghyde vertical loop (in 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 he hty *tgk s(gcp ,k3(pj0;svz, going?

  The maximum force a pilot can stand is about seven times his weight. hdx0 z 9sh9:,t1r j geq*a 3*c8pckgklWhat is the minimum radius of curvature that a jet plane's pilot, pulling out of a vertical dive, can tolerate at a spezpdx901ec :8rsck3g lajg hkq *h *t,9ed of 250 m/s?

  A car traveling 20 m/s rounds an 80-0 hl p6 m0rfym0tzrl..m radius horizontal curve with the tires on the 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 .hy0l0p0 . lrmzrf6tmeach road surface.)

  A car is negotiating a flat curve ofox+s;h 13 uvcw radius 50 m with a speed of 20 m/s. The centripe+wh sc3x1o;vu tal force provided by friction is $1.2 \times 10^{4} \; N$. What is the mass of the car?

  A car goes around a fl2t6nwmf+i 3ua at curve of radius 50 m at a speed of 14 m/s. What must be the minimum coefficient of friction between the tires and the road fwm623a it nfu+or the car to make the turn?

  A car is moving with a constant speed v around a level curve. The coefficmedm whhh3k*t 24hliuv88f 45 ient of friction between the tires and the road is 0.40. What is the minimum radius of the curve if the hkmhwu32 4hvf*8 i5l e4d8thmcar is to stay on the road?

  What minimum banking angle imfnpl +)uyny )f2yzek) fh,dvm)u- 7.s required for an Olympic bobsled to negotiate a 100-m radius .2ky)+f ,h7l ny fev)fnz -d)mmyu u)pturn at 35 m/s without skidding? (Ignore friction.)

  A horizontal curve on a bobsled run il5e i7hczb* p8vtjy*g7qar eo swv6 k8++ t;i4s 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 aq9unevra /s4v+b.hx - t an angle of $45^{\circ}$, may be safely negotiated at a speed of

  A curve of radius 80 m iss9 ,a; h;khfuy7so6j fq2ra9e banked 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 revolvin +g: gqdd2f,hna .2ozyt.0wwng uniformly in a horizontal circle of radius 0.5fz gwyhn tdg2q+0dno:a ,.2w.00
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, ag6ul9233zhragdvx:r 6v/fv p race car accelerates 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 v rvaz9dp r3f g2x6/:uhv 6g3lnumerical 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 consqpfj0k )5*apzmb,0(s4* uj x qpgy9 qbists 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 ud9witm*1hx ::i ic ;cperson standing on the Earth, due to th:u;d:x 9ic m* ci1thwie Moon? 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 masses is F. If the masses are9yjico// -z5hcxk 0sb movedkoz9h /x ji5s0-cy/cb to half of their initial distance, what is the gravitational attractive force?

  For a spacecraft going from the Earth toward the Sun, at what distanceyof) x5m;n oi. from the Earth will the gravitational forces due to the Sun and the Earth cannim ;f.o5x) yocel?
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 i zamktxclsuvn;(dt o2g 68*s;w 9 n,e:s $7.4 \times 10^{22} \; kg$ 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 ab/i/ky3 afaan 1ove the Earth equal to the radius of the Earth. What is her acceleration due to gravity?yka 3if/na a/1

  The radius of the Earth is R. At tf7dc 3w,h hd8what distance above the Earth's surface will the accelerati 8t,dcw3hdh7f on of gravity be $4.9 \; m/s^2$?

  A satellite encircles Mars at a distance above its svpknt14*; )mjcqe.c aurface equal to 3 times the radius of Mars. The acceleration of gravity of t)n tjkc* e;aqc1vmp4.he satellite, as compared to the acceleration of gravity on the surface of Mars, is

  At a distance of 14000 km from some planet's*zdf-qd zww9c9w3 t d5 center, the acceleration of gravity i3dwztd9d cq5z 9ww* -fs $32 \; m/s^2$. 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 has v3aq6*a sy6.wr,mqmv radius r. If the object is raised to a height oqymm 6w6 ,va.qr*avs3f 3r above the Earth's surface, what is its weight?

  By how many newtons does thnedjq m-i ;9qbh r79r5e weight of a 100-kg person change when he goes from sea level to an altitude of 5000 m? (The mean radius of the Earthe;mqd r-qnjb59 i 79rh is $6.38 \times 10^{6} \; m$.)

  The Earth has radius r. A satellite of mass 100 kg ise5bfk 91is 3hr whvn53 at a point 3r above the Earth's surface. What is the satellite's weh1 53s 95wehvbrik3 fnight?

  A spherically symmetric planet has fourso yw*b)wk -:f times the Earth's mass and twice its radius. If a ww-s *y)fob:k 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, Earth, and Sun all w(q)95 yqaezylie on the same line, with the Earth between the Moon and )e5ay(wzq yq9 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 t7 vtk gjho.:(wacwd;+ he 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., it just skims thekx-dj29* p z*xco+ eg1+clrba surface of the Earth). What is the speed of the satellite? (The mean radius+ - cpx* rdgaxc1elz+kob92j* of the Earth is $6.38 \times 10^{6} \; m$.)

  A satellite is in a low cii2 37 ga-js6gvd: y/keepggz* rcular orbit about the Earth (i.e., it just skims the surface of the Earth). How long does it takeeg-g/ p6 :edi7k3y *z gva2jgs 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 surfac7wgfgw blt9ay5ju* 9 y+3 kp,ye of the Earth. It is observed to have a period of 89 min. What is the mass of the Eartkfp9yj, *galutwb 97 gy+ 35wyh? (The mean radius of the Earth is $6.38 \times 10^{6} \; m$.)

  Europa, a moon of Jupiter, has an orbital diameter of ijst: el1-c7y$1.34 \times 10^{9} \; m$, and a period of 3.55 days. What is the mass of Jupiter?

  The innermost moon of Jupi(ueq cm; f9gc1/brn;b 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 rag gve3,unpw,,dius rvg, p3wn,ueg, , and moon B has orbital 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 is 8ql 0d -n;.bevi ijalounn2i*.8sb7s$7.78 \times 10^{11} \; m$ 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(i geq88a87-xr znetintp9w: is the average distance from Ju :7tqg 8w8a- nrpx8i(en9ize tpiter to the Sun? (The distance from the Earth to the Sun is $1.5 \times 10^{11} \; m$.)