Is it possible for an object moving with a ce,etf- a0 qd+xonstant speed to accelerate? Explainat de ,x0fqe+-.

  Consider a particle moving with constant9 o udglvv178b speed such that its acceleration of constantovg dub l978v1 magnitude is always perpendicular to its velocity.

  An object moves in a circular ck6 mn-+rpi,xxw xu2+path at a constant speed. Compare the direction of the object's velocity and acceleration vectors.x w xp+, cim2nukx-+r6

  When an object experiences uniform circular motion, the direction of the abq5 bbmbk rkk:8/02 phcceleratq k:mb/bh 2br0k8 p5bkion is

  Consider a particle moving with c(h uqa;c 6, ni(mom4aho- .yjwonstant speed such that its acceleration of constant magnitude is always pe o6.h-qwuoa4m,cjh;(na yi m (rpendicular to its velocity.

  What type of acceleration does an object moving with constant wn ))we,vv ikxk 5(9wt. cxp1nspeed in a circula9 niw( ekwk )w)tx5xvp.ncv,1 r path experience?

  What force is needed to make an object move in a cidhpk)lf:o(s-l a r8g a y+8gll 1)/ghprcle?

  When an object experielo+ ( sk(ms0+tmt *cq.hirhjf*l4s h*nces uniform circular motion, the direction of the net force s( qci++l(m 4ft*0shh*rmosh*ljt. kis

  A roller coaster car v+i4p 9 sdoy(qis on a track that forms a circular loop in the vertical plane. If the car is to just maintain contact with tra+ qydo i(s49vpck 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 z-dcfctajo )e+ 23lxf0(m v6qtrack that forms a circular loop (radius = 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 minimum valtxqccvj d fa+l0 e362 of(zm-)ue for its speed at that point?

  A pilot executes a vertical dive then follows a semi-circular arc until bfv88aezp9g ulki79 :it is going straight up. Just as the plane is f:uz97ki p9e balv8g8at 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 of radius r;9ytidbyhnk+ a 48: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. Then i .oj+js4 9pjrxt )nqq)t goes around the same curve at half of the original speed. What is the centripetal force on the car as it goes around4j) poj xrq. )9stqjn+ the curve for the second time, compared to the first time?

  A car goes around a curve of radius r at a constant speed v. Then it goes j 0,tpxq2elvw; 47hp-xf5yz g around a curve of radius 2r at speed 2v. What is the centripetal force on the car as it goes around the second curve, compared to the f;0g2pj7v -h,x54twypefzl q xirst?

  A car of mass m goes around a banked curve of radius r with spe tdpkgfni; 9j.fj1o);ed v. If the road is frictionless due to ice, the car can still negotiate the curve if the horizontal component of the normal forifn)1 ;9o;pjjfgdt .k ce on the car from the road is equal in magnitude to

  Two horizontal curves on a bobsled run a6 n0b y5o9ac8bb3 btmore banked at the same angle, but one has twice the radius ofban c5bb 63yb 8t0omo9 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 curve?

  The banking angle in a turn on the Olympic bobsled track is noqnif -t; 5set5qbcr);ck5 7*cpqc+h i t constant, but incre;qq5k5t7;5 cc+nrei sb ihc -ct *p)qfases 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 path to have both centrip9 z)0,g*f+xk)tfwk.:i ly */ de qw5qvryfl mzetal ayqvry, l5**zmkwwfl/+x)f:)qz0g . eik 9tfd nd tangential acceleration?

  The gravitational force bq9cp;tkl,ex; etween two objects is proportional to

  The gravitational force between tpag8* l ft-0az(e/idgyia3t cj -f6- two objects is inversely proportional to

  Two objects attract each other gravitationally. If the distance bet6l0 w8)6q1kv i 2t9iezd8fi vbr)ddbuween their centers is cut in d 6 r9vw)zu01f6ddq 2) vik lb88ietbihalf, the gravitational force

  Two objects, with masse6uq k8b 9jyycc5q.tp.s $m_{1}$ 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 mazf9geekn1;t n5g- a vwlj/+r u:6is7bsses $m_{1}$ 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 gravitaj0znp3dy:tw.b* glzkl.e-l ,kai v/ 3 tion.

  Compared to its mass on the Earth/mlnjj)g xk83 , the mass of an object on the Moon is

  The acceleration of gravity on the Moon is one-sixth what it is on Ea6.0 i nhpcy .n6ugonz;rth. An object ofo66n. hu.gp zyi0 ;cnn mass
72 kg is taken to the Moon. What is its mass there?

  As a rocket moves away from the E(a 6*pq. tjuys y/w7wuarth's surface, the rocket's weight

  A spaceship is traveling to the Moon. At wh t:-7 ydm5 oijvm1 2f(+pencjbat point is it beyond the pull of Earth's grav i-2n df:cp+(71btoyej5mm jv ity?

  Suppose a satellite were orbiting the Earth just above the surfac 1/y ow8nfhd0ke. What is its centripetal accelera wd/oh1kn8 fy0tion?

  A hypothetical planetrs.ww ++x b9io has a mass of half that of the Earth and a radius of twice that of the Earth. What is the acceleration due to gravity on theoww+xi9+b s. r 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 is on E:w cdsl3cr d.e(fu 36(pfcl:m arth. The radius of the Moon is one-foc 3l p(fcd(c6e sr.:f 3m:ldwuurth that of the Earth. What is the Moon's mass compared to the Earth's?

  Two planets have the same su5x3xwvzf 6 bl-x 9ds22ci4sd crface gravity, but planet B has twice the radius of planet A. If planet A has mass m, what isxsfzd -s6 43bcxx 2vd iw92lc5 the mass of planet B?

  Two planets have the sa 8tb8 /gr) mpoe)u0wsxme surface gravity, but planet B has twice the mass of planet A. If planet A has radius r, what is the radius of planets u0oe/gr x8pm))wtb8 B?

  Consider a small satellite moving in a circular orbit (radius r) about a sph n5xtu yodb0lj 670px3- 6mvo v6:1rskqytyq1erical planet (mass M). Which expression gives tomyx-qs v1b: 6 nlpq0dy37jtor6t6yu01kv 5x his satellite's orbital velocity?

  Satellite A has twice the mass of satellite B, andx5 +zuhgi, g7r rotates in the same orbit. Chr7x gg uz+5i,ompare the two satellite's speeds.

  A person is standing on a scale in an elevator accelerating downward. Compargdr xycy 8+f)8qdnd/8y2hn sk d4q +ux;d,6ave thdy d x 8,k2sd 8+x6ygqnqa d+rn/d4yh;)8fcvue reading on the scale to the person's true weight.

  Who was the first person to realize that the planets move in elliptical path 2tq.o,fx5z u()f t,oe1twi rps around the Sunw t)ufqf,5pettrz x1o2,( i.o?

  The speed of Halley's Comet, while traveqk7pvb7(4 f8d .qe1y2xp pl y thys(3eling in its elliptical orbit around the lb3ye. 7 dpphq(x8yfs 4pq2 yv 1e7k(tSun,

  Let the average orbital radius of a p1m0dzc)r6w he5 8htb vlanet be R. Let the orbital period be T. What quantity is constant for all plm c dzr)8 0wv1hbhe5t6anets orbiting the Sun?

  A planet is discovered to orbit around a star in the gala:-ndnqf8b uy4n1 d/ yxxy Andromeda, with the same orbital diameter as the Earthd1 y:ybx-/nq4 fn8 nud 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 defi44/hpc cszuq,/c-v fqned as one "astronomical unit" (AU). An asteroid orbits the Sun in one-third of a year. What is the asteroi fvcqzhcu-/p4,csq4/d's average distance from the Sun?

State Kepler's laws. zp4 p il*d,5(bott4f.y; qdss

  List the four fundamental forcesc43l +j0ac uqp in nature.

  An object moves with a constanzklyi/n abe.:+3wymw tv. h3,t speed of 30 m/s on a circular track of radius 150 m. What is the :3.i,kwabh.3y+ w /t levmnzy acceleration of the object?

  The maximum speed around a level curve is 30.0 km/h. What is the maximuv *y)u3y wz/5cb(yccs m speed around a curve with twice the radius? (Assume all othy ucs) y(yvw*/5zcc3ber factors remain unchanged.)

  What is the centripetal acceleration of a point on the perimeter of a bft w97py7v;uge/ clr/icycle wheel of diameter 70 cm whe/r9p7;7fg lyu/t v cwen the bike is moving 8.0 m/s?

  A point on a wheel rotating at 5.00 re-7+mxsw(y.zjuf6hw n k uae.* v/s is located 0.200 m from the axis. What is a7ewkhf-y wsjz(um6+*. ux.nthe centripetal acceleration?

  How many revolutions per minute must a circular, rotating space station of ra)sr w;c,n4wq k3n w/ .reek:gadius 1000 m rotate to produce an artificial gravity/ n wekc :sqg,)awe;43krrw .n of $9.80 \; m/s^2$?

  A motorcycle has a mass of 250 kg. It goes aroundvayk40 ; nz7hx a 13.7 m radius turn at 96.5 km/h. What is the c vkn0ya7 h;x4zentripetal force on the motorcycle?

  A 0.50-kg mass is attached to the end of a 1.0-m string. Txdg.ug,n/mkcviup np k)61 /.he system is whirled in a horizontal circular path. If the maximum tension that the strink.v nn).,upg mckigdu x/16p/ g 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 ava) (l *2h3gda :t olkn6moj) lev5vd6 strong string and whirled in a vertical circle of radius r. At the exact top of the path the tension in the string is h 6oak *g3 (6vno)jdldvv5lat2l ):em3 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 string and whirled in a ver-+tom u1,x xritical circle of radius r. At the exact bottom of the path the tension in the string is 3 times the stone's weight. The sto,m-o+x rx1i utne's speed at this point is given by

  A jet plane flying 600 m/s experiences an acceleration of 4g when 9ydrh1ul +ko(n*uby ,vi er64pulling out of the dive. What is the radius of curvature of the loop in wo*nrbr9,6 yluu1+4ye dvih (k hich the plane is flying?

  A pilot makes an outside vertical loop (in which the y w(iphf18 2jfn ( fhq/u2c)kicenter of the loop is beneath him) of radius 3200 m. At the top of his loop he is pushin1k(y 82i /q (fcj)iuw2ffhpnhg 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 weightj roeu0;hbhtt b xu*wj:n))1(. What is the minimum radius of curvature that a jet plane's pilot, pulling out of a vertical dive, can tolerate at a speed 1h) * u0)hjjoutb;xbnt( wr e:of 250 m/s?

  A car traveling 20 m/s rounds an 80- j b)q59t/k9bg:g;nje texdu1m radius horizontal curve with the tires on the verge of slipping. How fast can this car round a second curve of r tu);jgb1/xg9bejtdqn9k :e5adius 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 d9 l bf0(6:tmr+dmmrw-5scme i z7wq/with a speed of 20 m/s. The centripetal force providfciw 9+b0 6r d5dlmq: w/m(s rt-zmem7ed 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 ati qt9k 04tv+ljq;zh,u 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 th ,0;zt9h l4jk+qu qtvie turn?

  A car is moving with a constant speed v around a level curve. The zpw7q uf9s:l-coefficient of friction between the tires and the road is 0.40. What is the minimum radius of th-sf 97 wp:qzlue curve if the car is to stay on the road?

  What minimum banking angle is required for an Olympic glu:2d */cg bhbobsled to negotiate a 100-m c h:gub 2g*/dlradius turn at 35 m/s without skidding? (Ignore friction.)

  A horizontal curve on a bobsled run is bankedqm ps3wa( 5n.i 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 100brw,.gi :caa:yh:rx/ m, banked at an angle of $45^{\circ}$, may be safely negotiated at a speed of

  A curve of radius 80 )jz*t8e ctu zz4r)ba+m is 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 revolving unifor:cru b) ot:fpo9-g)ynmly in a horizontal circle:nofo )bp: yg-tcu9r) 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 at a uniform rate tfgp4/;u;rsph yj54t:o-vo2cd -x pebo a speed of 45 m/s in 15 s, moving on a circular track of radius fsr hvgc-5 -p42euyj ;ppb;ox4t/d:o500 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 consists of a proton(1bswtz9pitc(1:bdnk2/ sgxyv2v34v)x oby 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 personh 3 c bew)m9)hhwca(+g standing on the Earth, due to the Moon? The mass of the 9cwb(3 g) +hhehmc) waMoon is $7.36 \times 10^{22} \; kg$ and the distance to the Moon is $3.82 \times 10^{8} \; m$.

  The gravitational attractive force betfy6s(afa0sz3 5) .(i qkxlsxnween two masses is F. If the masses are moved to half of their isqail. 03s6)(n 5kafxz(y fsxnitial distance, what is the gravitational attractive force?

  For a spacecraft going from the Earthm36l*muln dm /k++ htk toward the Sun, at what distance from the Earth will the gravitational forces due to the Sun and the Earth hk+6 3lnl/dmu k+mtm*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 isre)+ (fyjq3i z)z hp:p $7.4 \times 10^{22} \; kg$ 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 qw 6nk3d+;ip. 0jy5z-sxpd cra distance above the Earth equal to the radius of the Earth. Whati0 wsdk+35.jcd-;qnpp yz6rx is her acceleration due to gravity?

  The radius of the Earth is R. At what distance above the Earth's surface wil*t fai2ax;n9d l th9f*daa txi2;ne acceleration of gravity be $4.9 \; m/s^2$?

  A satellite encircles Mars at a distance above its surm9h*a ( hd2y flb(;ckqface equal to 3 times the ;m *(9by(klfqh h 2cadradius of Mars. The 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 acceleration of-pvn1o (usw w, gravity is w(s,-w vp nuo1$32 \; m/s^2$. What is the acceleration of gravity at a point 28000 km from the planet's center?

  An object weighs 432 N on t;q3 y,,fbkmx4ux. qtcta7j1ofr -9is he surface of the Earth. The Earth has radius r. If the object is raised to a height of 3r above the Eaq-fksai mc;t1t73qxo . ,bf9r4,xuy jrth's surface, what is its weight?

  By how many newtons does the weight of a 100-kg person change when h n;a eo-2, 0nwoa(bhcse goes from sea level to an altitude of 500en;o sh a-2 n(w,bao0c0 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 a point 3r above thgux2 sv/ w(+, ajxfdz4e Earth's surface. What is the satellite'sdz jx,4vs u/ (2w+fgxa weight?

  A spherically symmetric planet has four times the Earth'1yg cu6hw*. j ey.3dgd5xe r8ps mass and twice its radius. If a jar o5h *..w3d6xedyejcr1gg y8 upf 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 lie oao2:9-j 4 ie ikb0tgbun the same line, with the Earth bebo92- 4uikebt g 0ai:jtween 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 the Moon.h 0day5od3oswm/pc ( 9t6 ffm-
(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 ju170g,af1 zhe3he 7 sbzado dq/afbh53st skims the surface of the Earth). What is the speed of the sat /dh zadef10bh1eh 3gfa7a5so,37bzqellite? (The mean radius of the Earth is $6.38 \times 10^{6} \; m$.)

  A satellite is in a low circular ,7/q vef by8q qt-x- obrb3;prorbit about the Earth (i.e., it just skims the surface of the Earth). How long does it take to make one revolution around the Earth? (The mean7q/tb ry8rp-;bb3q, v-xe qof radius of the Earth is $6.38 \times 10^{6} \; m$.)

  A satellite is in circular orbit 230 km abo+ ztsrd /e,o,jve 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 Ea/ strz +,jeo,drth is $6.38 \times 10^{6} \; m$.)

  Europa, a moon of Jupiter, has an orbital diameter ovsdmrx9um:r w 18;5 5-vajgwu:pg bd8 f $1.34 \times 10^{9} \; m$, and a period of 3.55 days. What is the mass of Jupiter?

  The innermost moon of Jupiter orbp tsjcz 00j,t9its 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 o 2+m dbni09fsnbr- ;wciafi;/n3p fc*rbital radius r, and moon B has orbital radius 4r. Moon A takes 20 days to complete one orbit. How long does it take moon 2 3cinif s nwpi ;/bb+dfrf 9cna-;m*0B to complete an orbit?

  The planet Jupiter iwxpaaeqk84 k k8jz1cs+ 7:wvr6 ba7u/s $7.78 \times 10^{11} \; m$ 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 is the average c ayzs+bk -o2acy6 0(hdistance from Jupiter to the Sun? c-h+(s k yz2byaca6o0(The distance from the Earth to the Sun is $1.5 \times 10^{11} \; m$.)