95.02: An object shown in the accompnjfbchc: 6j .5anying figure moves in uniform circular motion. Which arrow best depicts the net forcej cj6b5 nh:fc. acting on the object at the instant shown?

  05.31: A child is beltedzv0c tjui *u9dbt e6:+,z qy9w into a Ferris Wheel seat that rotates counterclockwise at constant sd6zuq+zy,j9tc 0eb:tu9 v wi *peed at an amusement park. At the location 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 j)8cd2 3j0 avmnyn:,u8o qbz+9ak gprat constant speed in a counter- clockwise direction. Consider a time interval duri29bdn jnug3 )+ja 8cor:0ma8kqvzp ,yng 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 velocity during this time interval?

  08.15: A particle continuously moves in a circular path at constant speedsh ;+ m1w:/jln rubvs,la/r5 u 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 ib+vs :,l/rmrus;l n5jh1a /w us 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 cloc;qy8szw8 z8haddwb :+ kwise with constant speed around the vertical circle shown. Which arrow best i z: s;8qaz8whd8 bdwy+ndicates the direction of the object’s instantaneous
acceleration at the point labeled X?

  12.11: A girl twirls a small mass connecte.8psv6x6 dwgpd to 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 thwpv 8xg6 d.6psrough 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 constant5 c le q9lp+8*ypso2ub speed around a horseshoe-shaped path as shown with the arrows in the figure. Which one of the following choices best describes the direction of the average accelerationl*pbs5e289oypq cl+u of the car in traveling from Wto X?

  08.35: Astronauts on the Moon perform apf-ue) l4mq9zn experiment with a simple pendulum that is released qu 4f9m)epzl- from 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 rests 2.0m from the cej2:s.h ;axotvnter 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, w .s;2jvtxo :ahhile the 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 pueipk.pe4n w /,ck moving in a circle of ,w ne4 ip.p/ekradius 0.5 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 thea+*w.z5ugb klkxx. q ) end of an 80-cm string rotating at a constzgqau+.*wkl k. )5xx bant rate of 4 times a second?

  09.24: A point mass moves along a horizontheg66cg0*l6 3s ws xn (qo5jw/ildqn8al circular path of radius 0.8m with a constant kinetic energy of 128J. What is the magnitwih66j nqc *gs8/s( q3dlge o50nw6xlude of the net force acting on the mass as it moves?

  96.24: A 2.0-kg ball is attached to a 0.80onfi7xt a6 71t m string and whirled in a horizontal circle at a constant speed of 6.0 m/s. See figure t6ift7 ot7xan1o the right. The work done on the ball during each revolution is:

  99.22: A child whirls a ball at the eny99ly.n/llz* u c9 nfrd of a rope, in a uniform circular motion. Which of the followin.9cfzly y*9l un 9rl/ng statements is NOT true?

  00.19: An astronaut in an orbiting space craft attaches ap i(kh+*u n.jmbnp m0,xy,n 9t mass m to a string and whirlsxtj+km0n9pun (p.,yh ni,b*m 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 motion would be

  07.22: A mass m is pulled outward until the string of length L to whie.90t2aibi8n ges(-y : qhwyqch it is attached makes a 90- degree angle with the 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 bottomh 2bsqwy-q ( ae tg0:i8n9iey. ofthe arc?

  94.15: A car is traveling on euv x6.a4utydkght;:by)2 ath8(*d ka road in hilly terrain, see figure to the right. Assume the car has speed v an8b ttydhu;)e( x*dkat 4v6:.2uy kg had the tops and bottoms of the hills have radius of curvature R. The driver of the car is most likely to feel weightless:

  17.10: A 2000 kg car1ir(*g ujelu4s atv, ini35s7 moves over a hill at a constant speed of 12.0 m/s. At the very top of the hill, the shape of the roa l1 st5a(rij4ugi7eu,iv*ns 3 d 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 the car?

  97.13: A small sphere is moving in a vertical circle at constp(n0zc +/hirx6j v i1uz;mam ;kwk34aant speed. The magnitude or ;3w4n kacaz/+uix 1p;mkhiv06 (zmj f the net force on the sphere

  11.47: A simple pendulum of length Lhasa point mass M released from restrko*- -gih ir2 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 forcei-h-2g rikr*o 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. The jy dtg1d(ca ,,mass is released from rest and undergoes simple harmonic motion. Which one of the following c,yd1tc ad,j(g hoices correctly ranks the magnitude of the tension in the string (T), the gravitational 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./, tq 0i,o ehupjacuu;lz5uby*nh.8( 0 newtons is applied to a rubber stopper moving at a 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 fpb hlja*y8,u c u /entoiz05(u,.hq;urequency f, of the stopper?

  05.28: A mass, M, is at rest on a frictionless surface, connected to a 1d ;-sz)dbaxo9hr+d zn 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 eqs-d; +oh drdx)z19azb uilibrium 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 kgb/oinlbe05pq;k) , o i mass with a constant speed of 3.24 m/s in a vertically-oriented circle of radius 0.75 m. What is the net forco ,epn;ib 0/ k5l)ioqbe 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 horizontmwu jk 3ue2dh+zuel k :)1ok1(al disk rotating at a constant rate about an axis perpendicular to the pl+h o l k(ekm1ku)w321jz:ueu dane of 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 stro+-oo6v s lpj370aw yu5;k vdartr1.d ing 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 6o;urjao-1ort+5 pvsd 30 .vyal 7 dkwan 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 shojp yf2q v3tm41iun;91 yw*lnpwn in the figure. The string to which the mass is attached has a length of L = 3. jf3p;l uymqn 1v12in4*yp9wt00 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 11.0u86.m re ;7a2x p.nrglf 6sikuwj )yf8g is at rest 30.0 cm from a horizontal disk’s center. The disk stafj 2 xgrfa i k8ru;.leyu6s nwm8)7p6.rts to rotate 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 kg is attached a distance R =1.7wo4x* qqqy *. ftjj-*j5 m from the fixed center of a disk as shown in the figure. The disk starts rotating from rest with constant angular accelerawf-qt.o qjy*q * *jxj4tion $α =5.00 rad/s^{2}$ 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,3u it 2a45v2xdg5rmtn starting at the top, with initial speed 17.0 m/s. t 24m3dxtvra5u2 ngi 5The object’s speed increases 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 1819pifids n+ v qox06i7.0 m/s. The object’s speed increases uniformly until itixs+d81o i0vin6p9f q 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 ifv*ukr + rd0k+2qp:z rests at the bottom 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 fas 2zuk0q+p+ irr*:dfkvt 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.