Is it possible for an object moving with a constant spe thi-tw )zjk6 2oo-+ohed to accelerate? Explain+hjhi t-) too6k2 wzo-.

  Consider a particle moving with constant spees yw gv2zr/v 04n64brs.c vp6s+g c:rpd such that its acceleration of constant magnitude is always b rscr0 sv:4pg6 . +rc/sv2vy 4z6ngpwperpendicular to its velocity.

  An object moves in a circular path at a 0jsxzk/u *-pjconstant speed. Compare the direction of*j jp-s0u x/kz the object's velocity and acceleration vectors.

  When an object experiencwos)0znhl /f 0,t7rgg es uniform circular motion, the direction of the acceleratil00g/w, 7hsftnr og )zon is

  Consider a particle moving with constant speed such that its accel;6ncdm m vey.cp3j 3v* b0u7gqeration of constant magn * ;3cbnvem7m6q3cjgdyp v.0uitude is always perpendicular to its velocity.

  What type of acceleration does an object movingj f*n3d1bvl0 zl4wp ;g with constant speed in a circular path egfw01 n3z4b; d*vp jllxperience?

  What force is needed to make an object movs+ hc2 j.ex:pj*v jwx7e in a circle?

  When an object experiences uniform c5g9d:mm /+pt 6hikpkp /wjyz3 ircular motion, the direction of the net forcw9gj+ptm y/ihpp5z:d m3 /k6k e is

  A roller coaster car is on a track /4cct e7 bmfn4that forms a circular loop 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 acceleration at this pcnc/7efm4 tb4oint?

  A roller coaster car (mass = M) is on a track that forms a circular )ufo7t jg2q;aloop (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 value for its speed at that p7gq2fa)jo u; toint?

  A pilot executes a vertical dive then follows a semi-cir(2vtxoy4dazpb7x t )8cular arc until it is going straight up. Just as the plane ty2v)dbxa(7 o4 tpz8xis 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 of radius x,i9-av o c7gw)y1b qf62*a rtbz-xyq$r$ 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 oq :y .2)drfdnw4 b5fuaround the same curve at half of the original speed. What is the centripetal force on the car as it goes udwy.bqfr2fd o :)5n4 around the curve for the second time, compared to the first time?

  A car goes around a curve of radius r an4 kp07bdsdbx qc )+e)t a constant 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 d )eq +4b7dksxcn )0pbsecond curve, compared to the first?

  A car of mass m goes (e2+b0xjugu go+-pef around a banked curve of radius r with speed v. If the road is frictionless due to ice, the car can still negotiate the curve if the horizontal componbfo2pg uu+e- 0 exj(+gent 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 t2b+bmp34 v8mt5 skwbvk0xdsy--0v pg he same angle, but one has twice the radius of+vy-w3b msx5-t0mkvs0vg bp8 kb42dp 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 not ccl ,0vfu 3ro; pu2lpk( n,t5eronstant, but increases upward from the horizontal. Cl3ne,uc(0p2t5vok ; pr,url foming 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 ccgk7 dh0)ta*2b(5 bnsw k/pvtircular path to have both centripetal and tangential acceleration? 75*t) kan2/(shbdb tvpcgkw0

  The gravitational forcekj)f+ hc 5;q-,shtgh d between two objects is proportional to

  The gravitational force between two objects is inverselya.zqd -x 4:a26zqk nf3 h9vtbf proportional to

  Two objects attract each other gravitationally. If the distance ps :c)7qpx0 4r7qdt u+n,hpuin6y c.lbetween their centers is cut in half, the .l ,tcciuxpn s+y6r47p 0 u7h:np )qdqgravitational force

  Two objects, with masses 2c(yldh48iyem h bl 12$m_{1}$ 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 masses n shn1,8a(rm;o u(aim fq8h.t $m_{1}$ 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 universallo k:+6gvkej05b ; -fvx0bck k gravitation.

  Compared to its mass on the Earth, the mass of an object on the Moonpga is9yc.f) 9 is

  The acceleration of gravity on the Moog 4cb/*;uzyxjt/ k8tt n is one-sixth what it is on Earth. An objec 8;bk xgyt *tu4j//ztct 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( vkn:tx,onep-hty 8t7zh9j7's weight

  A spaceship is traveling to the Moon. d9bdui wbaq0 i(t)i 11 At what point is it beyond the pull of Earth's gravity?b09itbuii d)a( w1qd1

  Suppose a satellite were orbiting the Earth just above the s-o(ynrc y.d1dpa2ru 8ah 1cm7urface. What is its centripetal accel 7p- adru1n2ycoa1c rdh(m8 y.eration?

  A hypothetical planet has a mass of half 9.;frn j xvzl8li vjh6900v)lssen 4wthat of the Earth and a radius of twice that of the Earth. What is the acceleration due to gravity on the planet in terms of n6vf0i9 vsn8v9 .jlwe) l zxl;js0r4hg, the acceleration due to gravity at the Earth?

  The acceleration of gravity -;d;ld0sha d bk6ri o,on the Moon is one-sixth what it is on Earth. The rad6lodrh i,-;akd0 ;sbdius of the Moon is one-fourth that of the Earth. What is the Moon's mass compared to the Earth's?

  Two planets have the same surface gravity, eqjb4jorgn5h5 9 y ojv848b /nbut planet B has twice the radius of planet A. If planet A has mass m, what rjeyj49noj bq88n/bgh 54 o5vis the mass of planet B?

  Two planets have the same surface gravity, but planet B has twice the mass of n(ji)6 4wq e8xsp0c xynel,c-planet A. If planet A has radius r, what is the radius of planet (ilwjs6ny n0e8 qe cp 4-x)c,xB?

  Consider a small satellite movinr l 50dmtf5ns76raha:g in a circular orbit (radius r) about a spherical planet (mass M). Which expression gives this satelliteflrth: ma0s75n ad 56r's orbital velocity?

  Satellite A has twice the massfldyd 187vh *f8lbu7b;il u3g2dfc 7q of satellite B, and rotates in the same orbit. Compare the two saddbli7cf ull 7vhy81*dguq7f ;8fb32tellite's speeds.

  A person is standing on a scale in an elevator 23w k(e dviz2ru*m;cijq 8bs, 2yi7tdaccelerating downward. Compare the reading on the scale to the person's true weight.mcki2w*,zb287; u j2vrtids3 eqyd (i

  Who was the first person to realize that the planets move in ellipticalqefnvkdr * wlxo03 *z hfwx;e;5 8t0i6 paths around f 6; r0oiwndz xe;x0vft *qkwl3e*85hthe Sun?

  The speed of Halley's Comet, while travla; jayt;kf.aj8zi( )+8gwt seling in its elliptical orbit around the Suzk;jf;8yt s+il a (g8atwja.)n,

  Let the average orbital radius of4ubcb o bsg:k*5r4b*f a planet be R. Let the orbital period be T. What quant s5 kgubc* br4o*bf4b:ity is constant for all planets orbiting the Sun?

  A planet is discovered to orbit ar9fnx cz(d141gdb1 ;fn(v ldv8at .rjr ound 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, what will the period of revolution of that new planet be, compare 9;.djvvn na1x(lbt 48zrf1rdcd( f1gd to the Earth's orbital period?

  The average distance from the Earth to the Sun is defined as one "astb9f. ;j tanlk5(l2tsvronomical unit" (AU). An asteroid orbits the Sun tl9fa;nkbj2(s 5tv.l in one-third of a year. What is the asteroid's average distance from the Sun?

State Kepler's laws. rgw+n/di pg:x+i7z/ x1yfg q5

  List the four fundamental forceg5oh ast t.wbk),s:q,+ cg1t ms in nature.

  An object moves with a constant speed of 30 m/s on a circular track of radiuszb h p(0a32zta jzk,h: 150 m. What is the acceleration of the objec z2htk ,bahza0z:jp3(t?

  The maximum speed around a level curve is 30.0 km/h. What is the maximum 8pcyg:zoly ,u 3qnfgbn./n70 speed around a curve with twice the radius? (Assume all other factoruq 3c7:yn f0pon8gy/, nglzb.s remain unchanged.)

  What is the centripetal acceleratio3fv b)iwsdplga- )-55: u v(xr/uusv on of a point on the perimeter of a bicycle wheel of diameter 7053sdw pl5 usvrfx-ou) ( ai :)buvv-/g cm when the bike is moving 8.0 m/s?

  A point on a wheel roimg8efm- f fyxg/,)44 ntbq8ltating at 5.00 rev/s is located 0.200 m from the axis. What is the centripetal accelerati -8fqy,4i/g48fbtmxeg)mn flon?

  How many revolutions per minute must a circular, rotatinoj2z/r, d k rtszd)bme-w33 f-g space station of radius 1000 m rotate to produce an artificiaf)t3mrz/s3ko, r-ejzbdw - 2dl gravity of $9.80 \; m/s^2$?

  A motorcycle has a mass of 250 kg. It goes around a 13.7 m radius turbtxaoucu2 z6t*s w;v:,jy jd 7(*ykg4n at 96.5 km/h. W6;*tztoyj gvxj2 yu:,a7s4cduk*(wb hat is the centripetal force on the motorcycle?

  A 0.50-kg mass is attached to the end of a 1.0-m string. The system is whirled0ur3kj7jm)p :m b9uxvh-ca6j 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 not to breau m a:b63m-)9prjkj70vucx jh k?

  A stone, of mass m, is attached to a s 83q.p nnwub(qtrong string and whirled in a vertical circle of radius r. At the exact top of the path the tqqn ( n3up8.bwension 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 a ha agudsbn4/7m(rd ypo7k991ttached to a strong string and whirled in a vertical circle ofdra/o7pb9dh4sn( ay1mug k 9 7 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 this point is given by

  A jet plane flying 600 m/s experiences an acceleration of 4g when pulling out x lr5f)tvg3 2vof the dive. What is the radius of curvature o3g5 xl)vrfvt2f the loop in which the plane is flying?

  A pilot makes an outsiy ;(j/lmu xad3de vertical loop (in which the center of the loop is beneath him) of radius 3200 m. uj;/ax(3 dmylAt the top of his loop 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 weigfe wui2scv *-3ht. What is the minimum radius of curvature that a jet plane's piw ie*vuc3-f2s lot, pulling out of a vertical dive, can tolerate at a speed of 250 m/s?

  A car traveling 20 m/s rmj f(lc*sjm ;.ounds an 80-m radius horizontal curve with the tires on the verge of slippingmscj *l.j;fm (. 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 each road surface.)

  A car is negotiating a flat curve of radius 50 m with a speed of 20 m/s. The ce /;ilox:wlchuqi.;6 kntripetal force provided by frictionol/6;. u:x ii ;ckwlqh 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 14 m/s.aod et b:h/+lh.41oqxxtb0. j What must be the minimum coefficient of friction between the tires and the road for the car to make the turnt0hb1ba d. x oqjohel:t+.4 x/?

  A car is moving with a constant speed v around a leve nw furty644kvnmqnz0+p / x6)l curve. The coefficient of friction between the tires and the road is 0.40. What is the minimum radius of the cur/tpumknxr 4vzny 64)+qf w6 n0ve if the car is to stay on the road?

  What minimum banking angle is required for an Olympic bobsled tlvaz ur )nblk:/n4 ;5bo negotiate a 100-m radius turn at 35 m/s without skidding?/ bb;n aul) 5l:rnvzk4 (Ignore friction.)

  A horizontal curve on a bobsled run is banked atoyqo d0mqmr -,4/r -fc 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, ba407p+gruvzdvwr 7 ;kd nked at an angle of $45^{\circ}$, may be safely negotiated at a speed of

  A curve of radius 80 ms2wi jmq6 pl494hv.uv/ yvq4q 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 revolvzildgg)(l5b x*ke2f *y j8w9ling uniformly in a horizontal circle of radius ilwl yl b)5xk2gz8*(edg*9jf 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 at9xim: hkes.- t a uniform rate to a speed of 45 m/s in 15 s, m9tih -sm.xk :eoving 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 consists 2bw63ji5aegi t 9mgqv8v7. nu 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 forc+ee9)rgkb :p*krk z q5ec u3r3e on a 70-kg person standing on the Earth, due to the Moon? The mass +k3bpqe*krze cur:kre 9g35)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 wseq )ax 2w2m6between two masses is F. If the masses are moved to half of their initial distance, what is tw)aw62m 2xseqhe gravitational attractive force?

  For a spacecraft going fropzu8 l,m7*nusr9t *ctm the Earth toward the Sun, at what distance from the Earth will the gravitationa* tt, s* urcm8lz79nupl 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 i72hjqiy :y1bmp7 4kess $7.4 \times 10^{22} \; kg$ 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 todfdlx4 zjq*ng9l+ /:w3 wef9l the radius of the Earth. W9w9fgld3+:l/we zfj*4n d xlq hat is her acceleration due to gravity?

  The radius of the Earth is R. At what distance a vbv5zhoq viactfr:3f3:6 ;d7bove the Earth's surface will the acceleration of gravitiv6:ho: 3v 3d7c5fvq;fzabrty be $4.9 \; m/s^2$?

  A satellite encircles Mars at a distance above its surface equal to 3 t :y1sn x3)s 9gplcb0riimes the radius of Mars. The acceleration of gravity of the satellite, as compared to the acceleration of gravity on9 i r)p0xs:c3lg byn1s the surface of Mars, is

  At a distance of 14000 km from some planet's center, the acceleration 9 yh5axjz:fma50np;q of gravity qaja9fyhp 0:x5n;5z m is $32 \; m/s^2$. What is the acceleration of gravity at a point 28000 km from the planet's center?

  An object weighs 432 N on the surfac cy5t/wv6p1 nmhxu0ixcn4/ ;ne of the Earth. The Earth has radius r. If the object is raised to a height of 3r abomx//t xn; 0c pun5w46vi1ynch ve the Earth's surface, what is its weight?

  By how many newtons does the weight of a 100-kg person change when heeai73 c y4v)qb goes from sea level to an altitude of 5000 m? (The meanva3ci b7qy)e4 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 the hun;ypp . pwd.kkg b6m:w6 c62s7ir- cEarth's surface. What is the satellid.6:6i7ycnwwursbp.- 6 p p;k2gck mh te's weight?

  A spherically symmetric planet has four times the Earth's ma/duo/-m8b yhea 8+nc hifo/4xss and twice its radius. If a jar of peanut butter weighs 12 N on the surface of the Earth, how much would it weigh on tih 8- 4efmaxuy8+n//oobdc/ hhe surface of this planet?

  During a lunar eclipse, the Moon, Earth, and Sun all lie on af9k350 b hfkgthe same line, with the Earth between the Moon and the Sun. The Moon has a massabhkk093ffg 5 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 transpogpif bme+5g+vuz4*eg6j :g 1aako9 -mrted 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 circular orbit mriaz1-v3n:7p1t l bsl) qt/xabout the Earth (i.e., it just skims the surface of t:srmxnv ti)p -lzl /171qt3abhe 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 the Ear v5hgmi) 4+qm+5eypppth (i.e., it just skims the surface of the Earth). How long does it take to make one revolution around theemv+p pqmh +pig5)4y5 Earth? (The mean radius of the Earth is $6.38 \times 10^{6} \; m$.)

  A satellite is in circular orbit 230 km above the su9a g 6n9+gkezgrface of the Earth. It is observed to have a period of 89 min. What is the mass of the Earth? (The mea9kgng9a + 6zegn radius of the Earth is $6.38 \times 10^{6} \; m$.)

  Europa, a moon of Jupiter,s8d2s7y po h ;mcoo*x9 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 orbits the planet with a radius vn:.gl p hlorn9/:bn;w0dg: 4d0oeb x of $422 \times 10^{3} \; km$ and a period of
1.77 days. What is the mass of Jupiter?

  Two moons orbit a pl aczy33 + jv 0m*ctr0vdc97gt,xxd7a;o :wlr canet in nearly circular orbits. Moon A has orbital radius r, and moon B has orbital radius 4r. Moon A takes 20 days to complete one orbit. How long does it take moon B to completa;a0tcg7mvow3jcrr0 ,dxv c:t 37zy +9cl*dxe an orbit?

  The planet Jupiter is(n84bnz 0k7(spf:tw kz az3fo $7.78 \times 10^{11} \; m$ 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 yeaw9p5i(7kky i(q *yppdzi8 6w,tqd- fmrs to orbit the Sun once. What is the average distance from Jupiter to the Sun? (The distance from the *qzpwyi8 ,tiiwm 5(d(kd9 -kq7f pp 6yEarth to the Sun is $1.5 \times 10^{11} \; m$.)