95.02: An object shown in thpg4uu+jwun l .+2+h(zm. .nbeaf kc:se accompanying figure moves in uniform circular motion. Which arrow (gchb z nk. f.4e u+p.musln2:+auj+ wbest depicts the net force acting on the object at the instant shown?

  05.31: A child is belted into a Ferris Wheel sea4akg*gl 5k*wl hq-6i.xihc*pm x33b w t that rotates counterclockwise at constant speed at an amusement park. At the loca ikpgca4wwq l*h* mi *.l 3xhk6g-3b5xtion 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 at constant speed i/xq8jars-d e1n a counter- clockwise 1/ja re 8qdx-sdirection. 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 velocity during this time interval?

  08.15: A particle cokmb7h4dxvcp n5x 61j2 ntinuously moves in a circular path at constant speed in a counter- clockwise direction. Consider a time interval during which the particle moves along thib14npmv2x 5k d6jh7 cxs 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 vertmut 8 ;oqp1)a+wy.m- flwd u4gical circle shown lywmmp;u1 w8fut d.+4 g)ao-q. Which arrow best indicates 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 ofh 3lr wfnsuz0d//d** f a string counterclockwise in a horizontal circle above her head. The figure shows an outlinzfnu 0*s3wld h*frd/ /e 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 constf7aht+ep7s m/ant speed around a horseshoe-shaped path as shown with the arrows in the figur7fma+etp7h/ se. Which one of the following choices best describes the direction of the average acceleration of the car in traveling from Wto X?

  08.35: Astronauts on the Moon perfrw9(kgdk5:0 )ol cb w(ktwfi.orm an experiment with a simple pendulum that is released from the horizontal position at rest. At the moment shown in the diagram wi5f(9k 0w (b.crk oltdgk ):wwith $0^{\circ} < \theta < 90^{\circ}$ , 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 cgb0edo+x(m. c2 0w tit ;sww3uenter 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. W0 u bwt2w;cmtie0s3w ( d+.xoghat is the magnitude of the force of friction acting on the object?

  07.19: What net force is necessary to k/b4xw 1jz y;6ydx9m dkeep a 1. 0 kg puck moving in a circle of radius 0.5 m on a horizontal frictionless surface with a s 1d94 xd/ymyxkj6wbz;peed of 2.0 m/s?

  05.03: What is the centripetal acceleration of an objectl* m kl0lmfp n5r;zcur5s522m (mass = 50 g) on the end of an 80-cm string 0nu2 r;csp* lzmr5 fk2m5lml5rotating at a constant rate of 4 times a second?

  09.24: A point mass moves sben64cf r0g d3y (c+jalong a horizontal circular path of radius 0.8m with a constant kinetic energy of 128J. What is the magnitude of tbec(+jr sc4n0d fyg36he net force acting on the mass as it moves?

  96.24: A 2.0-kg ball is attached to a 0.80 m string and fp9w3o)pirp ngmd8n18m e+7fr.r c3wwhirled in a horizontal circle at a constant speed of 6.0 m/s. See figure to the right. Tnwg8doefp8 pf mr )7rrcpw33+n1.i m 9he work done on the ball during each revolution is:

  99.22: A child whirls a ball at the end of a rope, in a uniform circular mot1pp0+ayp owo; ion. Which of the folapy0+ 1 oow;pplowing statements is NOT true?

  00.19: An astronaut in an orbiting space craft ad-2/q lfnxdh 0ttaches 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 mal 2d-hqnxd0 /fss, 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 )rh(* /rmckz+dmd / wyL to which it is attached makes a 90- degree angle with the vertical. The mass is relear /zk) wy(* mdc/mdr+hsed 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.87cvy thv47mq86 n zes Assume the car has speed v and the tops and bottoms of the hills have radius of curvature R. The driver of the car is most likely to feel ecthvmv 8y478zn7 6sqweightless:

  17.10: A 2000 kg car moves over a hill at a constant clrrp om 3d ;09t4pco: ke/qv -u4uh9xspeed 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 indica4x or 49d- pcvc0l39ohkeu/ rpqtum ;:ted 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 670kis* 51*tc/xrul; 8qmh k bjmytb jconstant speed. The magnitude of the nel8*h ubs rj;i/tmm0b yjt5*c76 x1qk kt force on the sphere

  11.47: A simple pendulum of length Lhasa point mass M releaskn.2x yd3wfh34q6x;r( e zgoped 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 fow.4dxfn 6 q3x(e;2grpzo kh3y rces when the mass swings at the bottom of the arc (point P)?

  16.32: A mass connected to a s kj31-l mypy 9(1tixbrtring 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 force on the mass (W), and the net force acting on the mass (F) when the mass swin 91pt(3j -b1miryklyx gs through its lowest point?

  04.41: A centripetal force of 5.0 newtons is applied to a rubber stopper mo1i/nd7 sikbstqp:49 bwq c:) fving at a constant speed in a horizontal cir iqscqwfdb9t:b1s :i7 n/p) k4cle. 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 ideal a94hrfwvn . 4vhorizontal 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 sw4av9h4 n .rfvpring 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 w e2r39 4yxz( /csl1rqb lluzz.ith 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 thbqyz2zl3s rxre(u.lc4 l /9z1e lowest point of the circle?

  14.23:Two small identical coins (labeled X andY) are at reston a horizont 3jdxkdwptm07( dw s3-al disk rotating at a constant rate about an axis perpendicular to ths07 -xdt3dwj3dwkp (me plane 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 stringsv 9xz3z u)6gl-pmydh09r4v n and moves about the string’s fixed end in a conical motion with a constant speed of 4.0 m/s. The st 6 p)3s9vr0gx49zz ml u-vhdynring 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 i/dl8o +w) 9in38zmnyt tpxar/ s in uniform circular motion as shown in the figure. The string t/nt+ t/za 8n yow38pirlxm) d9o which the mass is attached 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 cmnb ;w0-a 3tkl li9h;m+gxqg/s from a horizontal disk’s center. The disk starts to rotl; bg-0;a/sgw xmqlkn 3th+i9 ate 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 =1.75 m from 8 lkkcie;+sb1the fixed center of a disk akk1elsi 8c;+b s shown 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 p f9n d8w-hz 9,7bmb+2to ydvpa circle, starting at the top, with initial speed 17.0 m/s. T v,dh-y9 82p+9nzt bmpodfbw 7he 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, withr(;.oq6 zabv3o g5 hj/6 l pjijq3f+ht initial speed 17.0 m/s. The object’s spjql; ghvpqajfjto(6b536o .zihr /3+eed 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 time for this motion?

  17.38: A small 2.0 kg block rests at the bottom of a bucket. The bucket is spun 4 v r ery7ipjjeks+;18in a vertical circle of radius L by a rope. When the bucket reachjyv +rekrpe78s;i 4j1 es 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.