Is it possible for an object moving with a constant s.cduru zkg6:f r n2*4opeed to accelerate? Explain2 4zfkoc: 6du*r.gnur.

  Consider a particle movinur5c;nzglz p*;8/ r95p :mncezkr9pi g with constant speed such that its acceleration of constant magnitude is always perpendic5 5 9i9gzrzz lpr;8ncm* :;purknecp/ular to its velocity.

  An object moves in a circular path-s cpoxi8 s--zl fn,v5 fpmk:pse((c*;f w6c m at a constant speed. Compare the direction of the object's velocity and acceleration vecto f(p-pvcp ;*:klif5ss c-enz(cx68m ,os-wmfrs.

  When an object experi/k*kosnks db3w br 7:)ences uniform circular motion, the direction of the accelekkw * s3srbb)/od: 7knration is

  Consider a particle moving with constant speed such that its acceleratio, kucvs 9 ezr-lah)f*mh +)y 1+sjy0enn of constant magnitude i+ heshys )+j ky10 zfvn,m lrc*e)a-9us always perpendicular to its velocity.

  What type of acceleration does an object moving with con2 )e2*gp z) gevmo1wigstant speed in a circular pathmzwp1*og2g) eve2) i g experience?

  What force is needed to make an object mo)le3ef. ekhpdvq 1 +;tve in a circle?

  When an object experiences4hp83b(0duj ewiv :lj uniform circular motion, the direction of the net force 4p jvw0dbji :(leu3 h8is

  A roller coaster car is on a track that forms a circular ;2f6(bc pcg qaloop in the vertical plane. If the car is to just maintain contact with track at the top of the loop, what is thcq 6(;cfagpb2 e minimum value for its centripetal acceleration at this point?

  A roller coaster car (mass = M) is on a track that forms a circular loop (radoa zm2j : fooh63/be*aius = r) in the vertical plane. If the car is to just maintain contact with the track at the top of the loop, what is the/mof3 aoze2 *bhj6oa: minimum value for its speed at that point?

  A pilot executes a vertical dive then follows a s bld8,t+pr/)eeafy 0kemi-circular arc until it is going straight up. Just as the plane is at its lowest point, the b tap),0e8l fyr/edk+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 cuk+ qk rn(t)uwkk oj,srs:(/8vrve of 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 radil +6 q0578qp h +mbuyufdtpa(hus r at a constant speed v. Then it goes around the same curve at half of the original speed. What is the 7mq (u8 fpa5h h+b+yl0tqpd6 ucentripetal 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 spd3ls;e.csq vkxo c8c/ :z,uy 8eed v. Then it goes around a curve of radius 2r at speed 2v. What is the centrk.e,xs: ;cqv8 3ols 8cyd u/zcipetal 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 qxu,l )w ew 2e)(v6: zr:wfyjgr with speed v. If the road is frictionless due to ice, the car can still negotiate the curve if the horizontal component of the normal force on the car fro, wyrzxeq6 l(w2:euw fj )gv):m the road is equal in magnitude to

  Two horizontal curves on a bobsled run are banked at the same angle, but one rwd9hckym7+zj4/ h5e has twice the radius of the other9j7hm4 e5k / rwzhy+cd. 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 curve?

  The banking angle in a turn on the Olympic bo1by08.3jj*ky . zg3t+ vlxgbz xi0dm jbsled track is not constant, but increases upward from the horizontal. Coming around a turn, the bobsled team will intentionally "clij1zmg3 k 0db*vj8l. ygz.x 3y+ ixt0bjmb the wall," then go lower coming out of the turn. Why do they do this?

  Is it possible for an object moving around a citae0p2 y-4 de 6x,hh-wepku,63 q ejjarcular path to have both centripetal 6pj ,-d0e-huweyp k jax2tae ,qhe346and tangential acceleration?

  The gravitational force between1gbub z4zb +:h two objects is proportional to

  The gravitational force d*i w(ml12typ3 ups 6kbn zds26i4/mjbetween two objects is inversely proportional to

  Two objects attract each other gravitationally. If the dmf :vyt +h;ld4istance between their centers is cut in half, the gravit4+dl;t fym:vh ational force

  Two objects, with maskxsotfd3/g/8eb*+ v8q m n 1rfses $m_{1}$ 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 mao amk4ayl9by ;1 80estsses $m_{1}$ 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 univerfj x2ydpgc(jm1 9x0d)sal gravitation.

  Compared to its mass on the Earth, the mass ski*h.c:i6o;jw4 fsy i:zl s8of an object on the Moon is

  The acceleration of gravity on the Moon is one-sixm 6p*g.gr + ydbs7n/lyth what it is on Earth. An obje.ng6bgylspdr y +m7* /ct 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'skr)5ynne .b y+ weight

  A spaceship is traveling to the Moon. At what poi x ggo/w-lp;3x*ido.m nt is it beyond the pull of Earth's m/xw.xo ;-*ig o3ld pggravity?

  Suppose a satellite were orbiting the Earth jusycy )o8 l )2xm8qo/ennt above the surface. What is its centripetal accel2y lcn)8m xnoy8o e)q/eration?

  A hypothetical planet h7r8fyf5xu0(f,- eg w1;o;dovo i z epsas a mass of half that of the Earth and a radius of twice that of the Earth. What is the acceleration due to gravity oy8d1goe(e;w0f,5zvo xu- if7rp osf ;n the planet in terms of g, the acceleration due to gravity at the Earth?

  The acceleration of gravity on the Moon is one-six vqeb7.*ld*mw,5z its th what it is on Earth. The radius of the Moon is one-fourth that of thebvq, ltm*e*is w.5zd7 Earth. What is the Moon's mass compared to the Earth's?

  Two planets have the same surface gravity, but planet B has twice the radiusk0y8zq+rxu 9 7 9fyjrf of planet A. If planet A has mass qry7 f ju0r8 f9xz+k9ym, what is the mass of planet B?

  Two planets have the same surface b*qj jye 4e--ur*r, bfgravity, but planet B has twice the mass of planet A. If planet bfj-r y *4-qerue*,b jA has radius r, what is the radius of planet B?

  Consider a small satellitet lr;4doio rfo5-78kx moving in a circular orbit (radius r) about a spherical planet (mass M). Which expression gives this satellite's oro8r5o x 4ofrli7 ;ktd-bital velocity?

  Satellite A has twice the mass of satellite B, and rotates in the vw+*yd2lf pi h+q52 e *diyu7d qq-ol(same orbit. Cop(dhy qi2i-* lvq+qyefolu2dd* w7+5 mpare the two satellite's speeds.

  A person is standing on a scale in an elevator accf8 ;zad/* (ly3g ipxnielerating downward. Compare the reading on the scale to the person's true weight.y;d/3ap*izg(if 8 n lx

  Who was the first person to realize that the planed ir q2e xp-:zhm,+y/bts move in elliptical paths around the emph2yz b i,xr+-d /q:Sun?

  The speed of Halley's Comet, while traveling in its ebbf7y 4kllwc)9be9w d 4*i -wblliptical orbit around the Sun,k9-w4f7 w l9w )bbbydc*blie4

  Let the average orbital radius of wgf d*r(h*we j(fn*s ahs x738a planet be R. Let the orbital period be T. What quantity is constant for all plane8(f xgdn rh( e*3*saf wwj*7hsts orbiting the Sun?

  A planet is discovered to orbit around a star in the galaxy Andromeduk7p ;fy cj3h0a, with the same orbital diameter as the Earth around our Sun. If that star has 4 times the mass of pj hf7uk0y3;cour 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 dau-cd 04+le+dh fi5a9dotv8-nm)gtyefined as one "astronomical unit" (AU). An asteroid orbits the Sun in one-t 48tm i) +gu+hvdoneldcada y5 t--0f9hird of a year. What is the asteroid's average distance from the Sun?

State Kepler's laws.7bvma5cj xs14xld6( 42mkiiw

  List the four fundamental forces in natu d*vezl: gco0f:2ly 8wre.

  An object moves with a constant speed of 30 m/s on a6ok 4;7 gjv)ag,dbkn*im p5vq circular track of radius 150 m. What is the acceleration of vqd k4 ;, mjkbi6v *5gp)a7ngothe object?

  The maximum speed around a level curve is 30.0 km/h. What is the maximum speeaua2cq7 d8)tz0lkz h*:/ *5xlvn ogybd around a curve with twice the radius? (Assume all other factors remain t8k7 0z) qo5z 2vydb:l *c*lg/xnaahu unchanged.)

  What is the centripetal acceleration of a point onvy4ytkv98w7e mn. :uen 02 uhr the perimeter of a bicycle wheel of diameter 70 cm when the bike is moving 8.0 m/shv.teumw7 r0248uvn :y yek9n?

  A point on a wheel rotating at 5.00 rev/s is located 0.200 m from t6t9kjg -3(aioq zcf j lpe4.x7he axis. What is the centripetal acceleration?cg pf 6x3i74e.q kt-jl(z9joa

  How many revolutions per minute must(0vcn6m j j7 zb*g;kvl a circular, rotating space station of radius 1000 m rotate to produce an artificial gravjjl(*6zk7 b c g;v0nmvity of $9.80 \; m/s^2$?

  A motorcycle has a mass of 250 kg. It goes arouy9 7bjn3y.kmn nd a 13.7 m radius turn at 96.5 km/h. What is the ceny j7.39nnkbmytripetal force on the motorcycle?

  A 0.50-kg mass is attached to the end of a 1.0-m string. The system i8k4jpt h1 sg*zg;y,lq s whirled in a horizontal circular path. If the maximumyhl,z 8;*k4sp1j g qtg 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 attached to a strong string and whirled in a vertical ciryz/ju lnpph5y;wz,( : c:p( ,5/yhzyp u;ljznwle 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 point is given by

  A stone, of mass m, i; mwyp hjc ru)3tv9;2ps attached to a strong string and whirled in a vertical circle of r)j2prhu wv m;;cp3ty 9adius 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 this point is given by

  A jet plane flying 600 m/s experiences an acceleration of 4g when pupksahi(/*ar.9f) vd 4. aeqv jlling out of the dive. What is the radius of curvature of the loop iqpfirvkh 9j* .s4.d /)e v(aaan which the plane is flying?

  A pilot makes an outside vertical loohq; rt2c.9f zpp (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 9.qh;r t 2zcpfonly one-half of his normal weight. How fast is he going?

  The maximum force a pilot can stannzwz6ik0xyl qh pb-. s+v1 -*td is about seven times his weight. What is the minimum radius of curvature that a jet plan-sb .vxi kz6z0hw+1t* -lypnqe'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 horizwc r:vmqh5z( cm19 ak7ontal 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 k(9h7 5cr:wc1mmaqv z car's tires and each road surface.)

  A car is negotiating a flat curve of radius 50 m wp7s h.w*7s 3wht-m)q: li ces8w gg7bsith a speed of 20 m/s. The centripetal force pro) ss l.spq3mh -77wgh8twswe:*7 gbcivided 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 +x*po*8kqkoh9frx l wfm3)2bat a speed of 14 m/s. What must be the minimum coefficient of friction between the tires and the road for the car to make ) o3* * xxql2okb+ff8khw9rmpthe turn?

  A car is moving with a constant speed v around a level curveur3ayk: vo(k ). The coefficient of friction ( 3):ryuvo akkbetween the tires 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 bobsled to negotionpsj,1 ( yvmf:/ lya7q f7(.ph6q ciiate a 100-m radius turn at 35 mli7oscqh(vq:,py 1 7ny.pmia ff(j/ 6 /s without skidding? (Ignore friction.)

  A horizontal curve on a bocn yrl0 c+m;nd2v z-7wbsled 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,*sqp3kw1vr w;u :9em 1-uok wz banked at an angle of $45^{\circ}$, may be safely negotiated at a speed of

  A curve of radius 80 m is banked fo *c,qmvbt71 0)c/jpish; pye1h 3lb 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 horizontal 9fq30gb1k rw6rx3 zlt circle of 9 g0rxfr3b w6lk3 t1qzradius 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 caryyupv20w q5ehy9 g8z4g5t1j y 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 n491yg ev 8yywjupzhqy05 tg25umerical 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 proton of qp5sp- mx7ks 7mass $1.67 \times 10^{-27} \; kg$ 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 forch;0 ( gdtedru6e on a 70-kg person standing on the Earth, due to the Moon? The mass of the Mootgdr0hu(d e 6;n is $7.36 \times 10^{22} \; kg$ and the distance to the Moon is $3.82 \times 10^{8} \; m$.

  The gravitational attracsmh 0sr0h.jp+;iot -s tive force between two masses is F. If the masses are moved to half of their initial distance, what is the gravitatsj0 ss0tohm-h. i pr+;ional attractive force?

  For a spacecraft going from the Earth toward8grkm( ar42ox 9mui(j;jf. ua the Sun, at what distance from the Earth will the gravitational forces due to ox r fku8ju(m2(a9jra.img4 ;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 ib-u ;sc-+6emex ez vxcys -ifv6ej80.y* /ie bs $7.4 \times 10^{22} \; kg$ 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 disn17d1t jtfkvb*vu j hj p7+f3f9bfv)0tance above the Earth equal to the radius of the Earth. What i u fpfjn )v 3j+fj9b01vf1tvdbtk*h77s her acceleration due to gravity?

  The radius of the Earth is R. At what distance ahj6 2. )k4vdupsahg2hbove the Earth's surface will the acceleration of gravity be uhagp ks24vh2 )hj6d.$4.9 \; m/s^2$?

  A satellite encircles Mars at a distance above its surface equal to 3 timer w: 7xhsy80cds the radius of Mars. The acceleration of gravity of the satellite, as compared to the acceleration of gravity on the surface of 0xs8dw r7:ych Mars, is

  At a distance of 14000 x.ud3itb a(0u km from some planet's center, the acceleration of gravity is d (i uu03txb.a$32 \; m/s^2$. What is the acceleration of gravity at a point 28000 km from the planet's center?

  An object weighs 432 Nakz( rw fi (vbg;/2;t vg(zis- on the surface of the Earth. The Earth has radius r. If the obf;(ivzis -(ta/r(2g gv bw; zkject 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 when he goxrx9drmhp (.,es from sea level to an altitude of 5000 m? (The mean rad(xpr .r m,h9dxius of the Earth is $6.38 \times 10^{6} \; m$.)

  The Earth has radius r. A satellite of mass 100 kg is at a point 3r abq8i vr*z0o h6cove the Earth's surface. What is the satellite's weig 0vo*zr c6qih8ht?

  A spherically symmetric planet has four times the Earth's mooj-*h+6caazx0 .gx)a lh x4r ass and twice its radius. If a jar of peanut butter weighs 12 N on the surface orx o6aoxzhl4*-)c + ajha.g0xf the Earth, how much would it weigh on the surface of this planet?

  During a lunar eclipse, the Moo/*;ypyy9b xf nn, Earth, and Sun all lie on the same line, with by9;yn*f /px ythe 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 ball8 lb2ab2h2x. 2db uqizu b2,hk is transported 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 circ 099ud7 bh+ n5orldmhpular orbit about the Earth (i.e., it just skims the surface l9 ohr 0h7dpb+m5u9d nof the Earth). What is the speed of the satellite? (The mean radius of the Earth is $6.38 \times 10^{6} \; m$.)

  A satellite is in a low circular orbit about ti-1z q 3l8au3w 9xzpcvhe Earth (i.e., it just skims the surface of the Earth). How long doe3zp x1-l va u8c9qwz3is it take 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 or xp/ (klhljk +kyh: gbkv(-,*jbit 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? (The mean radius of the Earth k+(kypb jkg hkh-l/ j vl(,*x:is $6.38 \times 10^{6} \; m$.)

  Europa, a moon of Jupiter, hnl 5 nyucu69w.ohtdcm* q/ :0nas 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 orbits the lc,4pmtu vk,e9 d6qx 6planet 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 m b8;ektl 5jb8k4.s nqhu6m-i orbits. Moon A has orbital radius r, and moon B has orbital radius 4r. Moon A takes 20 days to complete tl4ke-6b nskm q;588jm.hibuone orbit. How long does it take moon B to complete an orbit?

  The planet Jupiter i pn q)i6:(l(sqeh v;pss $7.78 \times 10^{11} \; m$ 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 rc ed*y+jn:8lthe Sun once. What is the average distancde c y:n+8rlj*e from Jupiter to the Sun? (The distance from the Earth to the Sun is $1.5 \times 10^{11} \; m$.)