Is it possible for an object moving with a constant al:+)aoq8 njbybv1fp4j8b. f speed to accelerate? Explain 8ab qjv j1o.a4y p+8n:b)bflf.

  Consider a particle moving with constant spee h3 h1fy(;l upzeu5 itvpft6-8d such that its acceleration of constant magnitude is always perpendiculaph lf35zhiyp 61f ;8t-tue (uvr to its velocity.

  An object moves in a circular path at a constantxw4svv 0 og.b1 speed. Compare the direction of the object's velocity and acceleration vgwx0vs1 bo.4 vectors.

  When an object experiences uniform circular motion, t /wdyad nwt24(he direction of the acceley4 wt2/(adw dnration is

  Consider a particle moving with constant speed such that its accelerati kb2jur/98n;vy5)jylh k9r ifon of constant magnitudeku k28rnify ;9vr/jly 5 )9bhj is always perpendicular to its velocity.

  What type of acceleration does an object moving w7bjz6jig( 1u w3gjm4 sith constant speed in a circular path expezg4uj 3sb1m gi(w 6j7jrience?

  What force is needed to m slkod z:7.ey3ake an object move in a circle?

  When an object experiences uniform circular motion, the direction of idz3 vvr v;m5:the net force ismivrvv35d z; :

  A roller coaster car is on a track that fe3;8zih hicii x8u0 8torms 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 th 88tizeuii;c038 x ihhis point?

  A roller coaster car sx56 jjbqlem :5am 4 sw-sn4/i(mass = M) is on a track 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 min/5e :4s-x6wi 54mlasm jbqsjnimum value for its speed at that point?

  A pilot executes a vertical dive then followyp ob9bhh1i9 ,gz zl yybvw374x4yg((s a semi-circular arc until it is going straight up. Just as the plane is at its lowest poinyh7lxbi( 1z 99(3vg o4ph, wby4bygzyt, 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 ragt p-3 ,z+7. ijjuso n(slq7ft-tbyj8dius $r$ 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 constantke2tvsfq v2e-0-2-c2 kyawvt speed v. Then it goes around the same curve at half of the original speed. What is the centripetal force on the car as it goes arounq 20fvet-22 -v c -satvewy2kkd the curve for the second time, compared to the first time?

  A car goes around a curuq1rm;ma7z hv03u3*fpg8j 2iftg+ erve of radius r at a constant speed v. Then it goes around a cqaev fhf;zmp2j8 3*i1gutrum0 g 3r +7urve of radius 2r at speed 2v. 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 oce alp+)ifd bs*2uw+2f radius r with speed v. If the road is frictionless due to ice, the car can still negotiate the curve*sfpewcd+) iabl2u2+ 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 r(s3 9x -e v7ocwij2o-apv q2hqun are banked at the same angle, but one has twice the radius of the other. The hj- ov-c w3ipeq7x2svq9 o2(asafe 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 Ol yns.5ylhj:o ua9bp+jhy7 /h .ympic bobsled track is not constant, but increases upward from the horizontal. Coming around a turn, the bobsled team will intentionally "climb the wall," then go lower coming out of the turn. h. o7 jjs/nhy+hu y:9.lbpy5aWhy do they do this?

  Is it possible for an object moving around a circular path to c8x skro:l/5chave both centripetal and tangc:l so8k cr5x/ential acceleration?

  The gravitational force between :;y1eg z9badktwo objects is proportional to

  The gravitational force between two objects is inversely proportionatc5a+nce n 2 4gtc5g-je z-e9zl to

  Two objects attract each other gravitationally. If the distance between thl /e rdx2.ynyn(tx7r *eir centers i.2rtxxdnr ( ln yey/7*s cut in half, the gravitational force

  Two objects, with maso.f3 eykd9 dkupx*o3oh4i ummoj-; 59ses $m_{1}$ 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 massekb3fk-p6 3wq ts $m_{1}$ 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 gravitation. w, /qn ,ti9m3wy9 wxvpe:mowz;c8t4 w

  Compared to its mass on the Ears9uz 2ek 0w7pith, the mass of an object on the Moon is

  The acceleration of gravity on the Moon is one-sixth what it is on Earth. An xs;e a7c95t( p4do79ej q4xqxqjfn0vobjec0(p7dxjesvfj5;ocx4a7qeq4 t9 x qn9t of mass
72 kg is taken to the Moon. What is its mass there?

  As a rocket moves away from the Earth 4i0azx; 1zziud* .zlq's surface, the rocket's weight

  A spaceship is traveling to the Moon. At what point is it beyond hk *1 rk fg x4qf0ju2/*z:y9akmh4rztthe pull of Earth's gravi9x0h/z*1yamujfgk hr kk*t 4z:f4r 2qty?

  Suppose a satellite wereww pf+ :j-p(xe g+0pavuhxb+/ orbiting the Earth just above the surface. What is its centripetw/ +wxug +h+( bxp0av :f-jpepal acceleration?

  A hypothetical planet has a m +8ips )t s6vtxdvc+7a9 sk/owass of half that 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 g, the acceleration x8/ taicw pv)9sos6t d7vk+ +sdue to gravity at the Earth?

  The acceleration of gravity on the Moon is one-;ld 3 /d9 8b lymars7ssr-i-ctsixth what it is on Earth. The radius of the Moon is one-fourth that of the Earth. What is the Moon's mass compared to the Earat7lrbds8i - -d/c; y3s9mrs lth's?

  Two planets have the same surface gravity, but planet B has twic ne,n. m b7p+m/xl:+aznq. eppe the radius of planet A. If planet A has mass m, nn:q .,b+.ppnl7xpeemam/z+ what is the mass of planet B?

  Two planets have the samik: /wnul+oe k 7ctn7 my*6y13qf1 ckje surface gravity, but planet B has twice the mass of planet A. If planet A has radius r, what is the radius of plkm1 y1eufti6w7yj kqn3+ l/kno7c: * canet B?

  Consider a small satellite moving in a circula-py8:ciw6r-a tw 1ekc7tlo i7mm kz1)r u i3i3r orbit (radius r) about a spherical planet (mass M). Which expression gives this satellite's orbitaz71 3 i67wac p:-8mmlr-3kir ucyotw1kte)iil velocity?

  Satellite A has twice the mass of satellite B, and rotates in the same orbit.4 kplfj/ ;;tw k 74ekscc3yhn2i+zjb1 Compicf/j2k hkkeysw7;31pcn4+; l j4bt z are the two satellite's speeds.

  A person is standing on a sgfp;rxjdv.z ++p c upw-b, ,k14,pwy pcale in an elevator accelerating downward. Compare the reading on thv1rxp +kypupjb,d .fgpw+cp, w4;z,-e scale to the person's true weight.

  Who was the first person to realize t:2,p)c*gaagd+fpaj* vl j9eehat the planets move in elliptical paths around the Suj *a+f9apdg pe ,agjv*2cle) :n?

  The speed of Halley's Comet, while traveling in its elliptical orbit arnrdidt8 aiio.-9 +8 czound the Si8t+cr 9i-oi n.d8az dun,

  Let the average orbital radius of a planet be Rpvn/ 9 e8pae7b. Let the orbital period be T. What quantity is constant for all planets or9e/ v7ebppan8 biting the Sun?

  A planet is discovered to orbv82 h1 xdku+b*2cuu -cq.g8bqae gju7it around 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, compared to thej+q288.gad euhc1 u v-gxub27ub ck*q Earth's orbital period?

  The average distance from the Earth to the Sun is defined as one "q5* t* xgp wpcdqx/3c9astronomical unit" (AU). An asteroid orbits the Sun xpx3dc*g/q ptw *9c5q in one-third of a year. What is the asteroid's average distance from the Sun?

State Kepler's laws.)sfhk vzuv -*7

  List the four fundamental forces pb9vjq nw;:-s;c j s+fa7(gjbin nature.

  An object moves with a constantidfukj (8j (w4g 85zjt speed of 30 m/s on a circular track of radius 150 m. What is the acceleration of t8 fu5 tz8(jwi jj4(gdkhe object?

  The maximum speed around a level curve is 30.0 km/h. Wh ob9tp yx(r/r itb343yat is the maximum speed around a curve with twice the radius? (Assume all other factors biy 9p3t4ybrro x t/3(remain unchanged.)

  What is the centripetal acceleration of avtif tl-a:(0 m point on the perimeter of a bicycle wheel of diameter 70 cm wmav0-f :tlt i(hen the bike is moving 8.0 m/s?

  A point on a wheel rotating at 5.00 revor aoexa)nw 6+i,iw 1-/s is located 0.200 m from the axis. What6 woaia)wrei- x o1,+n is the centripetal acceleration?

  How many revolutions per minute must a circular, ru)k8f9koe, ypotating space station of radius 1000 m rotate to produce an a) k9yfk8u ,oeprtificial gravity of $9.80 \; m/s^2$?

  A motorcycle has a mass of 250 kg. It goe;.r6,j whug,e/on c zfq8 p0*r4rpkz is around a 13.7 m radius turn at 96.5 km/h. What is the c gqewjf 4.*/,couzi8,; 0n6pzrk rprhentripetal force on the motorcycle?

  A 0.50-kg mass is attached to the end of a 1.0-m strin5*mg(v v,9s bgip) tr(dwxluj,4rl k )g. The system is whirled in a horizontal circular path. If the maximum tension that the string can withstand is 350 N. What is the maximum speed of v ) j gmg p4klv5(i9rlwd* txu),(rsb,the mass if the string is not to break?

  A stone, of mass m, is attached to a strong string and whirled a 4-e-j ko;h ouzl5glosy6m: qfm6: d,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'd6hozsgj6quo-l: l 5e4kofamy;m:- , s speed at this point is given by

  A stone, of mass m, is atta6j. 6k;0xw + vwitnsbkched to a strong string and whirled in a vertical circle of radius r. At the exact bottom of t n6b tvk jx+;wks.6w0ihe 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 acceleratio/m g5jqk;q1jgn of 4g when pulling out of the dive. What is the radius of cjg;5g kqmj/q1 urvature of the loop in which the plane is flying?

  A pilot makes an outside vertical loop (in which the center 9pyza/61 mesn, shnu2 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 s6h, nu9p/zm as1nye2one-half of his normal weight. How fast is he going?

  The maximum force a pilot can stancfvh u,7hzs 70,djk -yd is about seven times his weight. What is the minimum radius of curvature that a jet plane's pilot, pullin , -,sf0kzhu7hjyd v7cg 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 horizontal curve with th. a/:a fb2ijroe tires on the verge of slipping. How fast can this car round aiajr :a.ob f/2 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 fliqb*4-fvdbu e 111ilzat curve of radius 50 m with a speed of 20 m/s. The centripetal force provided1-bvu biz1q lifed*4 1 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 at a speed of y7vmm 5w/:c em14 m/s. What must be tmw mve:5cy 7/mhe minimum coefficient of friction between the tires and the road for the car to make the turn?

  A car is moving with ukqel7y:m s/tg9.nx7 a constant speed v around a level curve. The coefficient of friction between the tires and the road is 0.40. What is 7tyn 9.ukegx:s mlq7/the minimum radius of the curve if the car is to stay on the road?

  What minimum banking angle is required for adx ;e,o *hgh+rn Olympic bobsled to negotiate a 100-m rar h g+*oe,;dxhdius turn at 35 m/s without skidding? (Ignore friction.)

  A horizontal curve on a bobsled run is banked 6t/ -ya k(exnogvl (y9at 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 at an angle of ra2;jgogv0: k8,h 5pvulznf*qk ii;+$45^{\circ}$, may be safely negotiated at a speed of

  A curve of radius 80 v00g:2 (a3e90ge pv 6she(x kct bkxeim 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 revolr3 s8ue-qt;e nving uniformly in a horizontal circle of radius 0te -uq;n 3ers8.500
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 ap9a t. fm..x xhcjde49rea, a 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 numerical valf 4c9 mh jtax.dp..x9eue 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 0u4cnn.r 3pqfx 4qnu6 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 the Earth, due to 80ew/ww ,f+q cwdy-osqkb/7p the Moon? The mass of the Moon is qwwky7sd0qoe8+p w-w/f /b c, $7.36 \times 10^{22} \; kg$ and the distance to the Moon is $3.82 \times 10^{8} \; m$.

  The gravitational attqvtkas03q ;,vractive force between two masses is F. If the masses are moved to half of their initial distka,t0;3 qqvvs ance, what is the gravitational attractive force?

  For a spacecraft going from the Eartoxzr06gww3a9d v 6k2j h toward the Sun, at what distance from the Earth will the gravitational forces due to the 09zra6w2 vgwokj x36dSun 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 bapjsais6z7f nde vl:)6vp/9op :2 4k 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 "space-walk" at a distance above the Earth equ xv5) 3p bz4vt03vpqmh5zo y(bal to the radius of the Earth. What is her acceleration bz 3 hv3vpvzoy4x p5m )(bqt05due to gravity?

  The radius of the Earth is R. At what distance above the Earth's surface wigf d; b, uzzj3m4bk4dib9.+rn ll thebdk.,bz4g;+9f idnb3 jurz m4 acceleration of gravity be $4.9 \; m/s^2$?

  A satellite encircles Mz4t : 9h, x l:ahy:nv(j1g5mzdqh0dpqars at a distance above its surface equal to 3 times the radius of Mars. The acceleration of gravity of the satellite, as compared to the acceleration of gravity on the shz ndga51dty(mqxp : vl0: 94:,qhjz hurface of Mars, is

  At a distance of 14000 km from some planet's center, the acceleration ofb 67l2e3:r95w zibhqd5m z rso gravity is 7bh:3d9m 5o5lz6w qzrbsi er2$32 \; m/s^2$. 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 ras ugeah(es gt 6yc(23.dius r. If the object is raised to a height of 3r above the Earth's surface, what y( gcss(g2utahe3 6.e is its weight?

  By how many newtons does the weigh-vans6+hma 3ao a/y. 9hbb-fn t of a 100-kg person change when he goes from sea level to an altitude of 5000 m? (Thaa soahn/ mfn3ah.vybb +9-6- e 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 6a 9 h6ien2r:x ltyx8p3r above the Eart6atxh6y9xl i8 e2:prn h's surface. What is the satellite's weight?

  A spherically symmetric planet has four times the Eljbhc 8w5 ;jq*arth's mass and twice its radius. If a bc;85jw hq* ljjar 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, E3w 0 .w7scgedd/s9hbs arth, and Sun all lie on the same line, with the Earthhw g/w9 s07bs.dse3 cd 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 ball is transport5p70hh 1 ezjkued 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 about the Earth (i.e., 7zd:u83 /lfele/h twbit just skims the surface of th7 t8 d uewlhfb:elz//3e 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 Earth (i.e., it4m, 5+2uw uookc.f/vk3sq j, epn+u ys just skims the surface of the Earth). How long does it take to make one revolution around the Earth.s5se j4,cn2yv/+o,ku uqpk f+m 3ouw? (The mean radius of the Earth is $6.38 \times 10^{6} \; m$.)

  A satellite is in circular orbit 230 km above the ernk4f7.g4s 0uiuzrhe4 +lp, 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 Eaif4elu,s erp+0uh.4 nk 7r4gz rth is $6.38 \times 10^{6} \; m$.)

  Europa, a moon of Jupiter, has an orbital diak -t7q 6-kkvb(lg4nf fmeter of $1.34 \times 10^{9} \; m$, and a period of 3.55 days. What is the mass of Jupiter?

  The innermost moon of Jupitia2elh w+wohqfe*62n:f ;h -o er 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 radi8dfrbq5x q2(7 yj3o0 /xe3nbf v/u 8v xs)myxnus r, and moon B haxsuv/ f(3 q /fbm 7qrx)ov8ejbx5n0nyd8 32yxs 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 i:.ecorkeqn+uhm . u; .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 J sh+,f)fc 8mfcupiter 12 years to orbit the Sun once. What is the average distance from Jupitc+f , mcfhs8f)er to the Sun? (The distance from the Earth to the Sun is $1.5 \times 10^{11} \; m$.)