95.02: An object shown in the accompanyinc f8ilj (se14sofgs9d2.rte*xw4 u- m g figure moves in uniform circular motion. Which arrow best depicts the net force acting on the object at*d8 slt -s(wifcomgf4 e9uej4sxr 12. the instant shown?

  05.31: A child is belted into a Ferris Wheel seat th,xy bsl5.o(s1 i(lx roat rotates counterclockwise at constant speed at an amusement park. At the location r.xs s1ioyl(o,l5x( bshown, which direction best represents the total force exerted on the child by the seat and belt?

  08.14: A particle continuously moves in(lc2a ba+ os3jnve f:* a circular path at constant speed in a counter- clockwise direction. Consider a time interval during which the particle moves along this circular p*of3lsn: (e v2+cb aajath 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 velocity during this time interval?

  08.15: A particle continuously moves in a circular path at constant sh/xuslh1(eh/ .byj kwe:(i3)j- wjzspeed in a counter- clockwise direction. Consider a time interval during. j (zy1heb()hsj3 shwewi/x:-ul/ kj which the particle 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 vertical bex t v+g+u d(c8 ba2x)g7cac7circle shown. Which arroc bbe8 7u2 dvaa++7gc(xcxg)tw best indicates the direction of the object’s instantaneous
acceleration at the point labeled X?

  12.11: A girl twirls a small mass connected tolyg3-y *c;+l ndr (iqi the end of a string counterclockwise in a horizontal circle above 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 letterr*cy-qdi i lln y(+;g3ed point on the path should she let go of the string?

  15.23: A car moves wi 85z08aul 09g6w fp +ofnltqczcz6bn6th constant speed around a horseshoe-shaped path as shown with the arrows in the figure. Which one of the fo6pzlc8 ffa9cz8b 5wzgu 0onq60lt+n6llowing choices best describes the direction of the average acceleration of the car in traveling from Wto X?

  08.35: Astronauts on the Moon perform an experiment with a simpc4x 3q -s 3i ejpmw.o9wce9lr5le pendulum that is released fr3 w9x3pe c clm-5sei.9q j4worom the 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 sulqo5hj qn*43; 9zga 75dsnsrests 2.0m from 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 thouh35q7slj a9 g*;nnq5s4 d sze coefficient of static friction is 0.80. What is the magnitude of the force of friction acting on the object?

  07.19: What net force is necessary to keep a 1. 0 kg puck moving in a circle ow j,x bi.hb+1w i pwppqw.(18qf radius 0.5 m on a horizontal frictppwwqi1+w8x p b,.1 q. (hbwjiionless surface with a speed of 2.0 m/s?

  05.03: What is the centripetal acceleration of an object (massw qqje8;y40xf o: 04mac8ulok = 50 g) on the end of an 80-cm string rotating at a constant rate of 4 fe uo:40ym4; oql80cwq8ka xjtimes a second?

  09.24: A point mass moves along a horizontal circular path of radius 0.8mnfk l(m xs1x)ff5ty :5 with a cm1n(5xlx fk )fys:t5f onstant kinetic energy of 128J. What is the magnitude of the net force acting on the mass as it moves?

  96.24: A 2.0-kg ball is attached to a 0.80 m sgy c6: 0hp89rz ftph6ptring and whirled in a horizontal circle at a constant speed of 6.0 m/s. See figure to the right. The work done on the ball pgr9 y:fht08c6p zph6during each revolution is:

  99.22: A child whirls a ball at the end of a rope, in a uniformlsim*qk z(:n bep,lfy)3 chwjj.;s *2 circular motion. Which of the following iz2h en:.j)*y3(,;*q mcjblp wfss klstatements is NOT true?

  00.19: An astronaut in an orbiting space craft attaches a mass m ttleknm o2- .25kq:i hxo a string and whirls it around in uniform circular motion. Thentq2 5 i.km :ox2khle- 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 maintain uniform circular motion would be

  07.22: A mass m is pulled outward until rd v(5fj bsi,4the string of length L to which it is attached makes a 90- degree angle with tr4v(sf ,jib d5he vertical. The mass is released from rest and swings 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 on a road in hilly terrain, see figure to the right.x*d2rk2w.r t f Assume the car has speed v and the tops and bottoms of the hilrw t. x*2r2fkdls have radius of curvature R. The driver of the car is most likely to feel weightless:

  17.10: A 2000 kg car moves over a hill at a:vi,79qezj xx)r+ jvq 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, :7v jrq) xxz+ive9qj the upward force exerted by the road on the car?

  97.13: A small sphere is moving in a v vs/x -q my7:9s93xeizfjbnm:ertical circle at constant speed. The magnitude of the net forc:9xmbv/xnj z:s9 f-qm7y e 3ise on the sphere

  11.47: A simple pendulum of length Lhasa point mass M released from rest9 9 yz-1a5.a0mt2w hw 1ovgqqzyv9qif from the horizontal position shown. In the absencevq2q59zov wyqy1. 9 z9th0if a1mg wa- 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 the arc (point P)?

  16.32: A mass connected to a stc: f0s2lqi.vd ring forms a simple pendulum. The 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 fo.f2c:si0 lqvdrce on the mass (W), and the net force 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 .f cz 2 a3zauvbs0;urcy18nv1 a rubber stopper moving at a constant speed in a horizonvcn v 2zfa 310y;uza.br1s8uctal 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 on0xl 0 q*1vb6nof lre1v a frictionless surface, connected to an ideal horizontal spring that is upstretched. A person extends thefle qon v r*x161lv0b0 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 of 3.24 nb2 if+n(rcr3m/s in a vertically-orienter 2crfi3+nb (nd 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) are at reston a horizoara (3u: ,ocdcdfm)+f)fa q4xntal disk rotating at a constant rate about an axis perpendicular to the plane of the disk and through its center. The distancam)u,r:(cfaf)+dq dxc3f4 oa e of the 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 the end of string and moves about th+awa;l k9 2vcyna*m *se string’s fixed end in a conical motion with a constant speeda+ys;v*ncl *a 2w 9kma of 4.0 m/s. The string has a length of 2.50 m and forms 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 showuj,bn.e5y:iz n in the figure. The string to which the mass is attn,je:yzb 5 ui.ached has a length of L = 3.00 m and forms an angle of $θ=50^{\circ}$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 fro0 ;8 04exsc .uof xmrqdxneo;/m a horizontal disk’s center. The disk starts to rox4; ;d00o8x sm/ nc eq.ufroxetate from rest about 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 with mass M = 2.0 kudged/slc lr0y;ie.*/xmar en9 2/k(g is attached a distance R =1.75 m from the fixed center of a disk as shown in the figure. The disk starty/9 *uelrexir dlg 2// a.(ck0en dm;ss 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 initx/bn:xzwhgn7 pq:q* ht0n u3/ ial speed 17.0 m/s. The object’s speed increax/ 3nngqnpqth/h:*bx7z : u0wses uniformly until it has moved counterclockwise 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 cm5 dhmk, )yoy) ki,4iaircle, starting at the top, with initial speed 17.0 m/s. The object’s speed increases uniformly until it has moved4 mh, miiyoy)kakd),5 counterclockwise through an angle 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 bottom of a bf,7aoagw2 o(yucket. The bucket is spun in a vertical circle of radius L by a rope. When the bucket reaches the highesaof (a yog72w,t point in its motion, it moves just fast enough for the block to remain in place in the bucket. 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.