95.02: An object shown in the accompanying figure moves in unifo ntop(2ouq py8: k0m1trm circular motion. Which arrow best depicts the net force acting on the objeoo :pt(yp1 2k uq8mnt0ct at the instant shown?

  05.31: A child is belted into a Ferris Wheel seat that rotates coun4sm9+ aymlk1pterclockwise at constant speed at an amusement park. At the locam4 y m+91akspltion shown, which direction best represents the total force exerted on the child by the seat and belt?

  08.14: A particle continuously moves in a circular path +,fslfea *ab mjp -a:*at constant 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. l,b: af+ p-sjmf*e*aa 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 circul/5jvvb4)syma 4gm6 qyn(;unsar path at constant speed in a counter- clocj4 (u a6 5ysgqns/yn ;vmm4)bvkwise 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 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 cib)tj; ,k v8ozdrcle shown. Which arrow best indj8zk , btdo);vicates the direction of the object’s instantaneous
acceleration at the point labeled X?

  12.11: A girl twirls a small mass connected to th8k:t hlhtnf 02 y gg*qxdm22p,e end of a string counterclockwise in a horizontal circle above her head. mt2k2gn 2*fh0,xt dg ly:8hqpThe 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 around a horseshoe-shaped ob/cu fzn. 2 cscq2(6 :nojcs,path as shown with the arrows in the figure. Which one of the following choices best describes the direction of the average acceleratio uscc2j os6onf(cbn :z,qc2./n of the car in traveling from Wto X?

  08.35: Astronauts on the Moon perform an experiment with cdb)81ikb 85 ;bhhj.d ecczn.a simple pendulum that is released from the horizontal position a bc1)j8ie5dc .; n8cdzkhb.bh t 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 objjv6:g n(qyul9 rb--yfd j;yi.ect rests 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 the coefficient of sta .ju y9g;vq6 lynrf:d(-iyjb-tic 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. 7r- l,y( hxurordm s *08c*xbj0 kg puck moving in a circle of radius 0.5 m on a horizontal frictionless surfac,7yh 8r0rd ub o-r(l*cjx x*sme with a speed of 2.0 m/s?

  05.03: What is the centripetal acceleration ofds 6mw4dg( pc +kh9n.if)/ jss an object (mass = 50 g) on the end of an 80-cm string rotating at a constant rate of 4 tiws) (f9dpsc4nm. ihd+kg/j 6smes a second?

  09.24: A point mass moves along a horizontal ciunh 2.5 rhjr(frcular path of radius 0.8m with a constant kinetic energy of 128J. What is the mag(nhrhu 2.rfj5 nitude of the net force acting on the mass as it moves?

  96.24: A 2.0-kg ball is attz4vk:;o j yza1x3evue-e 6cl1ached to a 0.80 m string and whirled in a horizontal circle at a constant speed of 6.0 m/s. See figure to the ro6 vjzey1uxvc4;k:e1l a- z e3ight. The work done on the ball during each revolution is:

  99.22: A child whirls a ball at the end of a rope, in a un9pfqr5uvr 1 j:iform circular motion. Which of the follo r rfj9qv1u:5pwing statements is NOT true?

  00.19: An astronaut in an orbiting space craft attaches a mass m to a striip+kv2pq* +lnrvjf// ng 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 maintain uniform circular motifip+/vnr2/ kq*vj+p l on would be

  07.22: A mass m is pulled outward until the stri4gugth- (;lmpw8 +n agng of length L to which it is attached makes a 90- degree angle with the vertical. The mass is released from rest and swings through a ;lw -gnauhtp8(g+gm 4circular 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 roxzd-vw1 bynr73 ;skq.ap8 x/p ad in hilly terrain, see figure to the right. Assume the car has speed v and the tops and bottoms of t1/xyw8.sz nqrdb-v;p7ax 3 kp he hills 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 hi -w5+ mrjg6 9y-hzap fl+.mfohll at a constant speed of 12.0 m/s. At the very top of the hill, the shape of the road can bea+ hz +9p y 6f-rlm-mogj.5fhw 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 the car?

  97.13: A small sphere is movkd zzg;b9 z;g.ing in a vertical circle at constant speed. The magnitude of the net force o zdzb;g k9zg;.n the sphere

  11.47: A simple pendulum of length Lhasa point mass M released frombyfk /ar4u bd40+) 79q5rcbbdxc u(nx rest from the horizontal position shown. In the absence of air resistance and friction, the mass swings through the ara dxxy4bq4uc kr)/u7 (d+5b cf9rbb0 nc 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 string forms a simple pendulum.am;u2mym6fo 1u kp 38n 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 gravitation u83mmo;k nm1y6pau2 fal force 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 a rubber stopper m9*5vo m ge+6m(to lwlkoving at a constant speed in a horizontal circle. If the same force is applied, but the radius is made smaller, what happens to them(o5 tl *elgokvw+69m speed v, and the frequency f, of the stopper?

  05.28: A mass, M, is at rest on a frictionless spx3+ywd 1j:;tw est2;0hi h7pfx tl2hurface, connected to an ideal horizontal spring that is upstretched. A 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 a7xw0dtxfi;p 2 ;+2 hw:hlyttj sp1eh3pplied by the person to hold the mass stationary there?

  12.22: A girl swings a 4i 1si rc3tlk50c;c1 io.0 kg mass with a constant speed of 3.24 m/s in a vertically-oriented circle of radius 0.75 m. What is the net force acting on the mass when it is at the lowest point o15ctol r0iiick 3 cs1;f the circle?

  14.23:Two small identical coin...vb5uq n vfavscaks3k8 :9h s (labeled X andY) are at reston a horizontal disk rotating at a constant rate about an axis perpendicular to the plane oq.9 nk5 svvufa: vhbk.8a3cs .f the disk and through its center. The distance 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 anr9, y23vb1tciqw tsr7kd1vj) d moves about the string’s fixed end in a conical motion with a constant speed of 4.0 m/s. The vwksjr71)itb3q1 dt, cy vr29 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 showtm-9 cjl u7*nwn in the figure. The string to which the mass is actlm*j u79nw- ttached 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 11.0h-j/ma 8a w (6a*0ln8)pu6k hsnunhalg is at rest 30.0 cm from a horizontal disk’s center. The disk starts to rotate from rest about its center with a constant angul)phn*lw u8nk- /hhs 6nj6aa8l(amu 0aar 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 kg is attached a gxobms7 2(5a9fy6alpdistance R =1.75 m from the fixed center of a disk as shown in the figure. The disk starts rotating from rest with constant angular acceal967pbm5a 2 fsg xoy(leration $α =5.00 rad/s^{2}$ 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,vtz6 15z7m7l0 nrpdn2w hpa t6 with initial speed 17.0 m/s. The object’s speed incrpzatd2nt 7z7nwp05 6mrvl 6h 1eases 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 circle, starting at the top, with initial speed 1716c pz(z ve0 p ;bg2mq2g.vofx.0 m/s. The object’s speed increases unifozzv 0fg 2pg1o2m(p eb6.;cvxqrmly 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 time for this motion?

  17.38: A small 2.0 kg block rests at the bottom of a bucket. The bucket is spunkmx w6t 69u/xv in a vertical circle of radius L by a rope. When the bucket re/kw m 66txvu9xaches the highest 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.