95.02: An object shown in the accompanying figure moves in unxht:d ;fq*i oms* kh890csv5tiform circular motion. Which arrow best depicts the net t*59o8c0 k;hdqiv ssx*m tf:hforce acting on the object at the instant shown?

  05.31: A child is belted zq, yzuw36 me66evq/ga c+13*htn wwsinto a Ferris Wheel seat that rotates counterclockwise at constant speed at an amusement park. At the location shown, which directiomhq 36va,*gwtn 63w6ue y+ezcz 1qs w/n best represents the total force exerted on the child by the seat and belt?

  08.14: A particle continuously moves in a circular path at constanr +ltduoh n5+*t speed in a counter- clockwise direction. Consider a time interval during which the particle moves along this circular path from point P to point Q. Point Q is exactly half-way around the circle from Po rldo*t+u+ n5hint P.
What is the direction of the average velocity during this time interval?

  08.15: A particle continuously moves in a circular path at constant smh, eet*t/x +speed in a counter- clockwise direction. Consider a time interval during which the pats h/,xem* +etrticle moves along this circular path from point P to point Q. Point Q is exactly half-way around the circle from Point P.
What is the direction of the average acceleration during this time interval?

  15.07: An object moves clockwise with constant speed around the vert6iw 4vuh.z/hmq;ole 7 ical circle shown. Which arrow best indic/h7 hoq4 uz;l ivew6m.ates the direction of the object’s instantaneous
acceleration at the point labeled X?

  12.11: A girl twirls a small mass connected to the end of a t:ynnkzswz fkk1+i w1j1.do -ps76 6cstring counterclockwise in a horizontal circle abov k1w ijok cdn wnzs1ysk:6t76-1pfz +.e her head. The figure shows an outline of the mass’s path viewed from above the twirling mass. If the girl needs the mass to pass through the point labeled P in the figure, at which lettered point on the path should she let go of the string?

  15.23: A car moves with constant speed aroun 3u rzwwjei87/u3bx6leb; d-id a horseshoe-shaped path as shown with the arrows in the figure. Which one of the following cii7rx;-3 b dbz8uj36l weewu/hoices best describes the direction of the average acceleration of the car in traveling from Wto X?

  08.35: Astronauts on the Moon perform an experimrdqf*u h0rk (.ent with a simple pendulum that is released from th .qkdr*0 fu(rhe horizontal position at rest. At the moment shown in the diagram with $0^{\circ} < \theta < 90^{\circ}$ , the total acceleration of the mass may be directed in which of the following ways?

  03.19: A heavy (2.0 kg) point-like object rests 2.0m fro,czv7 dbiih2z-) be f-m the center of a rough turntable as the turntable rotates. The period of the turntable's rotation is 5.0 seconds. The coefficient of kinetic friction between the object and turntable is 0.50, while the coefficient of static friction is 0.80. What is the magnitude of the force of friction acting on the ohdvi, -)izc27zb- be fbject?

  07.19: What net force is necessary to keep a 1. 0 kgw2) tg27jevkx puck moving in a circle of radius 02)gv ewk7jt2 x.5 m on a horizontal frictionless surface with a speed of 2.0 m/s?

  05.03: What is the centripetal acceleration of an object (mass = 50 g) on vlwc al cvz5rr/4nhmt) y*t/;w );p z6the end of an 80-cm string rotating at a conzc6z *a vm4n ;l;w)pr5lw) yvr/h/ cttstant rate of 4 times a second?

  09.24: A point mass moves along a horizontal circular path of radrr/i+ (tjf1pt ius 0.8m with a constant kinetic energy of 128J. What is the magnitude of the net force acting on t/tt jp+(1frri he mass as it moves?

  96.24: A 2.0-kg ball is gpx 65s3g+qvx:2 jjze attached to a 0.80 m string and whirled in a horizontal circle at a constant speed of 6.0 m/s. See figure topq j+2xjgsex6g v5:3 z the right. The work done on the ball during each revolution is:

  99.22: A child whirls a ball at the end of a rope, i,w r3h. /s8gvcw5um sbn a uniform circular motion. Which of the following statements is/, 8r wss.um3 wg5bcvh NOT true?

  00.19: An astronaut in an orbii2o-m8a yit h- az0h jkh):cs/ting space craft attaches a mass m to a string and whirls it around in uniform circular motion. The radius of the circle is r, the speed of the mass is v, and the tension in the string is F. If the mass, radius, and speed were all to double the tension required to mainta za0hh a2 8tj)/io-k-hymci: sin uniform circular motion would be

  07.22: A mass m is pulled outward until the sr-)5i mluerhgu 82h;)d-sjxhtring of length L to which it is attached makes a 90- degree angle with the vertical. The mass is released from rest and rhudih-ur;hsje-m5 x))82g lswings through a circular arc. What is the tension in the string when the mass swings through the bottom ofthe arc?

  94.15: A car is traveling onmsvxsuk/ qn(.ov ( jy*j .p)te.9ih v8 a road in hilly terrain, see figure to the right. Assume the car has speed v and the tops and bottoms of the hills )qvjiv j.*nv.u(xhso/pk (t.ym98 sehave radius of curvature R. The driver of the car is most likely to feel weightless:

  17.10: A 2000 kg car moves over4tsxi729jk gl8q t, ps a hill at a constant speed of 12.0 m/s. At the very top of the hill, the shape of the road can be approximated as a circle with radius 25 m, as indicated in the figure. Which one of the following choices best represents the magnitude of the upward force exerted by the road on the28 ksl7 gjtpt94,xsiq car?

  97.13: A small sphere is moving in ayyq,9)4 a lb 2hhhvkg(rap9z 2 vertical circle at constant speed. The magnitude of thhkz4a2y99gv l)2h qabh( , prye net force on the sphere

  11.47: A simple pendulum of length Lhasa point mass M released9+ymte uy+j ymd ,,c8d from rest from the horizontal position shown. In the absence of air resistance and friction, the mass swings through the arc of a circle. Let T represent the magnitude of the force from the string on the mass (tension), G represent the magnitude of the gravitational force acting on the mass by the earth, and F represent the magnitude of the net force acting on the mass. Which one of the following choices describes the relationship among these forces when the mass swings at the bottom of j yeyc,du8 ty+ ,dm9+mthe arc (point P)?

  16.32: A mass connected to a string forms a simple pendulum. Tueway bw (1ef0:11 xiphe mass is released from rest and undergoes simple harmonic motion. Which one of the following choices correctly ranks the magnitude of the tension in the string (T), the gravitational force on the mass (W), and the net y1fipe0 xbww: (u1ea1force acting on the mass (F) when the mass swings through its lowest point?

  04.41: A centripetal force of 5.0 newtons is applied to a c39de/ic.wwy po s+zx e5i)l8rubber stopper moving at p5i.xy/zs8oec3 w+)d9lwi eca constant speed in a horizontal circle. If the same force is applied, but the radius is made smaller, what happens to the speed v, and the frequency f, of the stopper?

  05.28: A mass, M, is at rest on a frictionless surface, connected to an idfe50y+a.qk 3j2 np mnxeal horizontal spring that is upstretched. mjn x2q0ypk+ 3f5.neaA person extends the spring 30 cm from equilibrium and holds it at this location by applying a 10 N force. The spring is brought back to equilibrium and the mass connected to it is now doubled to 2M. If the spring is extended back 30 cm from equilibrium, what is the necessary force applied by the person to hold the mass stationary there?

  12.22: A girl swings a 4.0 kg mass with a constant speed or+d8 e:nv, qdyf 3.24 m/s in a vertic:q,+ dy8rendvally-oriented circle of radius 0.75 m. What is the net force acting on the mass when it is at the lowest point of the circle?

  14.23:Two small identical coins (labeled X andY) 0a)z ,i g(93l :pwnjnjo-cuud are at reston a horizontal disk rotating at a constant rate about an axis perpendicular to the plane of the disk and through its center. The distance of theu:9az, nj -0gpucnldjiow3) ( coins from the center of disk is related by $d_x=\frac{1}{2}d_x$. Which one of the following choices correctly identifies the relationship between $f_x$and $f_y$ , the frictional force on coin X and on coin Y, respectively?

  15.40: A 2.0 kg mass is connected to u4xbomv nhv/ *w cpyech 7*38,the end of string and moves about the string’s fixed end in a conical motion with a constant speed of 4.0 m/s. The string has a length of 2.50 m and forms em/*38yc xuvh7 ch4no*v,pw b an angle of $θ$ with the vertical. What is the tension in the string?

  17.26: A 4.00 kg mass is in uniform circular motion as shownee,kw3 )5pt*4o jmzip in the figure. The string to which the mass is attached has a length of L = 3.00 m and forms an angle opwkt m,j3o *i5zee4p )f $θ=50^{\circ}$with the vertical. What is the speed of the mass?

  13.23: A small object of mass 11.0g is at rest 30.0 cm from a horizontal disupi 5gxwks54ms2 as (o;e38vgk’s center. The disk starts to rotate from rest about38s sv(is 55apmog;w4e2kxug its center with a constant angular acceleration of $4.50 rad/s^{2}$ . What is the magnitude of the net force acting on the object after a time of t=1/3 s if the object remains at rest with respect to the disk?

  10.35 A point object wiqp: iyv:en8 vz j03(rrth mass M = 2.0 kg is attached a distance R =1.75 m from the fixed center of a disk as show i0r3v(e:yv pjr8z qn:n in the figure. The disk starts rotating from rest with constant angular acceleration $α =5.00 rad/s^{2}$ about an axis perpendicular to the plane of the page through the disk’s center. After how much time (in seconds) is the tangential component of the point object’s acceleration equal in magnitude to the centripetal component of the point object’s acceleration?

  16.39: An object moves in a circle, starting at the top, with inite w :0oxa:4qxtd a4of+ial speed 17.0 m/s. The object’s speed increases uniformly until it has moved counterclockwa0 q +odo4ax4wef:xt:ise through an angle of$55^{\circ}$. The average acceleration for this motion is $9.8 m/s^{2}$directed straight downward.
What is the final speed of the object?

  16.40: An object moves in a circle, starting at the top, with initial slp1m0my 6s:q speed 17.0 m/s. The object’s speed increases uniformly until it has moved counterclockwise through an angl q :0my6ssml1pe of$55^{\circ}$. The average acceleration for this motion is $9.8 m/s^{2}$directed straight downward.
What is the time for this motion?

  17.38: A small 2.0 kg block rests at the bot)8.bqlxn* o zptom of a bucket. The bucket is spun in a vertical circle of radius L by a rope. When the bucket reaches the highest point in its motion, it moves just fast enough for the block to remain in place in the *xl. n)oz8qp bbucket. When the bucket is at an angle $θ=30^{\circ}$from the vertical, as seen in the figure, what is the magnitude of the normal force (perpendicular to the surface) provided by the bucket onto the block? Note that the direction of the gravitational field is indicated in the diagram byand that the block does not touch any sides of the bucket aside from the bottom of it.