Is it possible for an object moving withvbt 7wywb myd;3/p:l) a constant speed to accelerate? Explai :ydywl7p3 mtb/)w;bvn.

  Consider a particle moving with constant speed such that its accelerau8ow/,j8lj d u49zoz ztion of constant magnitu,u/u4zo olwd8jj8z 9zde is always perpendicular to its velocity.

  An object moves in a circular pp+qgaz.k9 m zvx-kt;3 ath at a constant speed. Compare the direction of the objeq 3 agz k.+xvmpktz-9;ct's velocity and acceleration vectors.

  When an object experiencurez rh)i.jki0w5g /+es uniform circular motion, the direction of the acceleration iw+.iir) g hrzk5u/e0 js

  Consider a particle moving with constant speed such that its accelersiw6p2- (3kcmo u6fd pation of constant magnitude is always perpendis p(32d-k m6fcopi6wucular to its velocity.

  What type of acceleration does an object moving witb0)5 *jifk gksh constant speed in a circular path experieb k0kji sg5f*)nce?

  What force is needed to make an ob(b yk5 pk+-p plc p7hvtg-lbey e:9/:eject move in a circle?

  When an object experiences uniform circular motion, the direct ao+gex m1:(icion of the net force aocx:+ge(mi1 is

  A roller coaster car is on a track that-kqbpq acjat*(6-e a 08tuhj. 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 minim- qajtk. 86ah 0e-uq(ajb *ctpum value for its centripetal acceleration at this point?

  A roller coaster car (mass = M) is on a track that forms a - qy3j j 1kpvk9ulye8v kh 5/vzl0o:p)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 value for its speed a5v9/)y8p-zvvek 3p y0k :lj johqkul1t that point?

  A pilot executes a vertical dive then follows a semi-circular0k7e0b3) rijhz aswp; arc until it is going straight up. Just as the plane is at its hj wpk)0srbi0; e3za7lowest 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 . rsmw :e9cr*n$r$ 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 spzn*.d1idjd: +br qpp0 eed v. Then it goes around the same curve at half of the original speed. What is the centrpibd01r :*q jzn+. pddipetal 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 speed v. Th4o vujxl8dx2.z485haj9 lukjen it goes around a curve of radius 2r at speed 2v. What is the centripetal force on the car as it goes around the second cuvlh9248 djuuz jx 8k5lo4 jx.arve, compared to the first?

  A car of mass m goes around a banzolq 2 gp:yg6(j bd4nf1mad+b9 (ay+tked curve of radius r with speed v. If the road is frictionless due to ice, the car can still negotiate the c+dtm4g :a2z +byyjga 16n (pfoqb l(9durve 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 say5br(peg -q e97jsk*yme 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 ongqp(y9*7-y k b5r eejs the larger radius curve?

  The banking angle in a turn on the Olympic bob*r ka u4.y3ohfsled track is not constant, but increases upward from the horizontal. Coming around a turn, the bobsled team will intentionally "climb the wall," thena h kr3o4ufy*. 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 c vg a;g3)9briqentripetal and tangentiavg3;igbr9a)q l acceleration?

  The gravitational force between two obthqa,4 7i bte:4o3f.3qvg6, axuptu8u8mhaj jects is proportional to

  The gravitational force between two objects is inversely proportiona 0nhc-lhzt d44(ajz, al to

  Two objects attract each other gravitationally. If the disc5,6qogf snj.nur o3xr *on 02tance between their centers is cut in half, the gravitatgnqn.j5, csor2*fx 3o60 ronuional force

  Two objects, with mass6orls0+ yod 1oes $m_{1}$ 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 mass:+n9-sc8gebnc df cz5es $m_{1}$ 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 unk qi m, 2w+e1aqyv8dt5iversal gravitation.

  Compared to its mass on the Earth, the mass of an object on the Moon islcpsjj/gn z/:x1:)8/ (e ahihhxl0l)9m khtw

  The acceleration of h5 xdooc/vf/ss. 8u-bgravity on the Moon is one-sixth what it is on Earth. An obje5od/s hu co-x.s/8bv fct 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's we-xoc w6hi6eqsv 8p+ -might

  A spaceship is traveling to the Moon. At what point is it beyond the pull ofe-l-04-b wk9udmf d ca Earth's gravit-c k-f-damuw0 4 de9lby?

  Suppose a satellite weqbl n0w- tbm+51uaj +nre orbiting the Earth just above the surface. What is its centripetal aj-t 1+q0b+5 nu wmlabncceleration?

  A hypothetical planet has a mass of half that of th1 / g5s jhw7k7uib0rqoe Earth and a radius of twice that of the Earth. What is the acceleration due/o5q r1s7wj0 hi 7ubkg to gravity on the 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 Earth.m7,ey s,u4/evvyogj+m nq u), The radius of the Moon is one-fourth that of the Earth. What is the Moon's massvugyu ) 7m+/ y4 ne,oe,,mjqvs compared to the Earth's?

  Two planets have the sa p y*r2s6sy .ear)lsu( wc5.pnme surface gravity, but planet B has twice the radius of planet A. If planet A has mass m, what is sa p..srw)y2 5ncu*ypr l(s6 ethe mass of planet B?

  Two planets have the same surface gravit1wyc bpw23e m)y, but planet B has twice the mass of planet A. If planet A has radius p2mw)y w1eb c3r, what is the radius of planet B?

  Consider a small satellite moving in a circular orbit (radius r) abwvwlxd+1 m( y1-1 +jqi5qp xxwhac t*,.r-ishout a spherical planet (mass M). Which expreswi., p(r1wq1-+wx mx+ cs- 1htdxyh j5ilvqa*sion gives this satellite's orbital velocity?

  Satellite A has twice the mass of ul o*9d)nxbax)fwg 91satellite B, and rotates in the same orbit. Compare the two satellite's spe*og) xb9n91u fa)xdlw eds.

  A person is standing on a scale in an elevator accelerating downwaal+t :r88q5au0r f yoard. Compare the reading on the scale to the person's true weia 0lrra8uqy8 to:fa5+ght.

  Who was the first person to realize tia uy+j(nzm6/hat the planets move in elliptical paths around th6/(zjym + inaue Sun?

  The speed of Halley's Comet, while traveling in its elliptiycw)hy7 :.bu vcal orbit around the Sun,)vy:. h7ucyw b

  Let the average orbital radim2mqk h8yyn2f 9 681bpi u,fvrus of a planet be R. Let the orbital period be T. 1, bmfmr28n6hy upf2 iv yq89kWhat quantity is constant for all planets orbiting the Sun?

  A planet is discovered to orbit around a staadna1)qfh: ukb2z*ws : zr7*x r 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, compared)bn7zar12 fk sa d:*q:wz*hxu to the Earth's orbital period?

  The average distance from the Earth to the Sun is defined as one "astronomic3gh8mut 9ygh:a*q(iaw 85i sbal unit" (AU). An asteroid orbits the Sun in one-third of a year. What is the asteroid's averagh:aqatmbi(*38g 5h9y sw8 iu ge distance from the Sun?

State Kepler's laws.o/f;rx u(qa5grh5 nq8

  List the four fundamental forc )wt o29t-i4f5t9sgsqgt n ii7*um8pses in nature.

  An object moves with a constant speed of 30 m/s on a circular track of radi ,iq 9ig)nl;lpus 150 m. What is the acceleration ,q;ilnl9gi p )of the object?

  The maximum speed around a level curve is 30.0 km/h. What is tgbnwg. kc6ve-6 oy-g8 he maximum speed around a curve with twice the radius? -8egy nkgc6-gwvo b.6 (Assume all other factors remain unchanged.)

  What is the centripetal acceleration of a point on the acd;waixc3 j. lui .24pgw* :7j)u ikeperimeter of a bicycle wheel 3uui4 accek *piiwljg j.2.x7:);dwa of diameter 70 cm when the bike is moving 8.0 m/s?

  A point on a wheel rotating at 5.00 rev/s is locatezwc3 ha 0kx+o9zbs,:e d 0.200 m from the axis. What is the centripxz,kzo9b s30:ca +wh eetal acceleration?

  How many revolutions per minute must a circular, rotating s7q8 os 6m1)5ev jygjje4h*l popace station of radius 1000 m rotate to produce an artificial gravity l4 s jv*)o gm1j6q8ehp7oy5je of $9.80 \; m/s^2$?

  A motorcycle has a mass of 250 kg. It goes around a 13.7 m radius turn at 96.r7 u2 z2djpvlisf59o: mn8 ,zr5 km/h. What is the centripetaoi 5rn mzv9df:2j s8r zu27,pll force on the motorcycle?

  A 0.50-kg mass is attached to the end of a 1.0-m string. The 6i.3 qqgs6gzz system is whirled in a horizontal circular path. If the maximum tension that the string can withzg6q3 is6z.g qstand 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 ojgf05wwezr.e)-,g l to a 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 point is given be l0w5gzgj.r,w ef-)oy

  A stone, of mass m, is attached to a strong string and whirled in a vertic7wo9pj n:jk:ft ko4h;al circle of radius r. At the exact bottom of the path the tension in the string is 3 times the swojkp; hn4okf:t 9:j7tone's weight. The stone's speed at this point is given by

  A jet plane flying 600 m/s experiences an acceleration of 4g whenlvhc zmkwi3pr+mc55 b:2i q 44; tkoz0 pulling out of the dive. What is the radius of c mz3r0hii54kovc4ct;wkz p5:+q bm2lurvature of the loop in which the plane is flying?

  A pilot makes an outside vertical loop (in which the center of the loop is 0ljgezm,6 nstm 55wf9pq9 5jqbeneath him) of radius 3200 m. At the top of his loop he is pushing down on h5qtemgf9swlj6 jp 0zm,9q 55n is seat with only one-half of his normal weight. How fast is he going?

  The maximum force a pilot can stand i/)pn3tt8 eghbwgx1e1 n u,t,p s about seven times his weight. What is the minimum radius of curvaturht3wgxubte)/ gen,11p8t np , e 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 8 fkn) ;dauqijh *s5b35/cyck00-m radius horizontal curve with the tires on the verge of slipping. How fast can this car round a sec 3u;ni5jsa qkbfkch)d50/y *c ond 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 7cs8cai)f pc;a speed of 20 m/s. The centripetal forcea pf)ci;c7s8c provided 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 mg. yor q1g,jq2 o2kdl, at a speed of 14 m/s. What must be the minimum coefficient of friction between the tires and the .l,2doqjyg k,1o 2grqroad for the car to make the turn?

  A car is moving with a constant speed v around a lc 8dko0k7 hmjlku9b12k j:2 noevel curve. The coefficient of friction between the tires and the road is 0.40. What is the minimum radius of the curve if the l8khm0 k:2jb 1d7n okcko j9u2car is to stay on the road?

  What minimum banking angle is ubqlw0bsm7 )9required for an Olympic bobsled to negotiate a 100-m radius turn at 35 m/s without skq 9)lbb u7w0smidding? (Ignore friction.)

  A horizontal curve on a bobsled run is lrfft.0 -6foxqz 1h-h 7bs4 alg:u2clbanked 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, baahwa b;8y6u09rq5,bglnus k5nked at an angle of $45^{\circ}$, may be safely negotiated at a speed of

  A curve of radius 803lza2n:ub ,j n 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 uniformly .y4iw nx:,9n,vf .);atz+dfldgna b .qy 8ghein a horizontal circle of radius 0f8xtn+z.y,dahbe9ql) i ;a 4ggyn d f,..nv :w.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 accelerau*tr0in0eo c8 tes at a uniform rate to a speed of 45 m/s in 15 s, moving on a circular track of radius 500 m. (only fil inc08te*oru 0l 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 co;x6uayz2h.,kix: sr 4uc9d vynsists 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 person standing on+g/s, m)m7hmhhedse: the Earth, due to the Moome7s edghhsh+mm/:, )n? 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 y1 qpafok(p -+ag.i8s F. If the masses are moved to half of their in go sipa-qy(p8k1 a+.fitial distance, what is the gravitational attractive force?

  For a spacecraft going from the Earth toward the Sun, / b uwbo/:pcy0at what distance from the Earth will the gravitational forces due/:pyb0/ocbwu 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 Moonka d0os 451eyrb 64eaw is $7.4 \times 10^{22} \; kg$ 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 "egw*l7r 8zzy;space-walk" at a distance above the Earth equal to the radiuyl *r e7wz8z;gs of the Earth. What is her acceleration due to gravity?

  The radius of the Earth is R. At what distance above the Earth's surface w 8 uy;1v ybzkm+ w5elefx:h:n8ill the acceleratix81:vk;5m8z ey ywb+:u nelhfon of gravity be $4.9 \; m/s^2$?

  A satellite encircles Mars at a distance above its surfaz0xa0r+.ip gy/;;u-hsr ptfd ce equal to 3 times the a/ yh.gdu0 xzfipp+st0; r ;r-radius 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 fc b) xr96ou c)qn,n/ffrom some planet's center, the acceleration of gravity iq)fux / o,6ccfnn )9rbs $32 \; m/s^2$. 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 Ear2byxjs3d u*qe* z3rion*jg3 +th. The Earth has radius r. If the object is raised to a height of 3r above the Earth's surface, what*yq3d2*ux3esgjj rb * zin3o+ is its weight?

  By how many newtons does the weight of a 5o/w- ,brdjii tn3a-o100-kg person change when he goes from sea level to an altitude of 5000 m? (Theiw,or oiaj/ - ndt3-5b 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 a6+d+xojf1mx m point 3r above the Earth's surface. What is the satellite's weigxm1 dj m+x+o6fht?

  A spherically symmetric planet has four times the Earth's mass and twiv,jzye,,,u v jce its radius. If a jar of peanut butter weighs 12 N on the surface of the Earth, how much would it weigh on the sur,uj,,,zy vvj eface of this planet?

  During a lunar eclipse, the Moon, Earth, and Sun all lie on the same li;/v: s hknu9buc rd5f1ne, with the Earth between the Moon:u k bcdn9frvs;u /h51 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 ir lm3xk tl9gwb87;g9ks 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 circular orbit a::f7ei1:f+fey s3ki- ezdk9clvpm( f bout the Earth (i.e., it just skims the surface of the Earth- +:kd s9efii:f7p(:m fkecy13 elzvf). 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 f r9vs;1ydd3zEarth (i.e., it just skims the surface of the Earth). Howdzvf 3s9dy1;r long does 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 orbit 230 km above the:d 5u vcag*8ax 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 a85 vg:*dacxuthe Earth is $6.38 \times 10^{6} \; m$.)

  Europa, a moon of Jupiter, has an orbital diametsrpi6+7wc m kn7/k4pu er 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 m* r,otijdvg,30ki z(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 orb 1y*aax;*q u rf/t9qo)rm(d moits. Moon A has orbital radius r, and moon B has orbital radius 4r. Moon Ara ;mta*1rd/ )y( q* o9quxomf takes 20 days to complete one orbit. How long does it take moon B to complete an orbit?

  The planet Jupiter i6,w3uj.x: upp3:ml j:cpcos fs $7.78 \times 10^{11} \; m$ 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. W l2 iwrpruwd bgo64+-i;+n- qxhat is the average distance from Jupiter to the Sun? (The distance frw-ow4 r2qi+ 6x; gdup+rinb l-om the Earth to the Sun is $1.5 \times 10^{11} \; m$.)