95.02: An object shown in6n o 3kj+b6px7is 4i 0mzdq.w+hf7a il the accompanying figure moves in uniform circular motion. Which arrow best depicts the net force acting on the object at the instan+3.6isp0 in w6ai7q4dl fhmxoj+ kz7bt shown?

  05.31: A child is belted into a 9 +q6ir3t dkmfFerris Wheel seat that rotates counterclockwise at constant speed at an amusement park. At the +9tk d3mf6rq ilocation 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 circulazv,* s 4t, f37jjctdigr path at constant speed in a counter- clockwise direction. Consider a time interval during which the particle moves along t,zv sft,j7tjg34d *i chis 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 nfez:y6 3yp*m speed in a counter- clockwise direction. Consider a time interval during which the particle moves along this circular path from point P to:*n6zym pyfe3 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 verte yh1e :.ujs v+t0jlje3kp ce+a1.5kbical circle s0+kpeyh:v u .1tabj+kjc5j1l3e . eeshown. 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 connssdey1 a0- *g6tayq wc+m m*9+yi )jtfected to the end of a string counterclockwise in a horizontal circle di *6a-ttm)jmgyc1+qy+ y0 ew 9sa*sfabove 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 alf:czp+ r ox( m/6 j52hswku6eround 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 acceleration/ pxj 6k:es5+ l(ohucm6rwfz2 of the car in traveling from Wto X?

  08.35: Astronauts on the Moon perform an experiment phm- mbmzbw+w: 8: jb8with a simple pendulum that is released from t8h wmpb-b8m jzbw: +:mhe 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 cen+8ycpwzy5x oj8y wvd;3jz,1ster 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 obj8y; sx+ jz o,y5p1dw8jw yzvc3ect 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 object?

  07.19: What net force is necessary to keep a 1. 0 kg puck moving in a ci 9nv57v opu 8q;cksn3crcle of radius 0.5 m on a hori5q8vc 73vs9puo nckn; zontal frictionless surface with a speed of 2.0 m/s?

  05.03: What is the centripetal avtvbg i z96yps0q 13w+fou9jri/ v+cf5e+ sq5cceleration of an object (mass = 50 g) on the end of an 80-cm string rotating at a constant sfso+b5 qt gvu1cqpfe /9935 v jyi0+6v z+iwrrate of 4 times a second?

  09.24: A point mass moves7tu78rw d (yrq along a horizontal circular path of radius 0.8m with a constant kinetic energy of 128J. What is the magnitude of the ne77qdw y(t8rru t force acting on the mass as it moves?

  96.24: A 2.0-kg ball is atr mrfe 1e4p;j1a4 yfh*tached to a 0.80 m string and whirled in a horizontal circle at a constant speejy1r; h14p f4eamfr*e d of 6.0 m/s. See figure to the right. The work done on the ball during each revolution is:

  99.22: A child whirls a ball at the jgn/i4 . ai7o,tu1jx/cqo/h fend of a rope, in a uniform circular motion. Which of the following statements is NOTcu .gxnoot1f /h4/iqaj, 7j/i true?

  00.19: An astronaut in an orbiting space craft attachesr )hu;w5e3vgmuawcwd9zw 8 3 ) 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 te))gu5mv wcw 3hw8wr du;z9ae3 nsion required to maintain uniform circular motion would be

  07.22: A mass m is pulled outward until the string of length L to which it is gteey 1vz3nke 3lk(: 6attached makes a 90- degree anglnkzv1(eek3 e 6:tgy3l e 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 bottom ofthe arc?

  94.15: A car is traveli0xcvozamw(mpv7 f-no/-m 3 z*ng on a road in hilly terrain, see figure to the right. Assume the car has sm3cn zz* o-pvfvm7( x0wm/oa- peed v and 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 car moves over a hill at a constant spey7 n8+eyj vu+o-ji nd.ed 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 2ny.u7vi -jno+ + jdy8e5 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 convf;pud s85wz0 stant speed. The magnitude of the net force on theu8s0z5 dfvwp; sphere

  11.47: A simple pendulum of length Lhasa point mass M released from rest from d0m otn:wg+ s4k/1n:.lsc qquthe 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+unkd4tm0l 1q/: wc nqo.gss: 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 mas2g q uiztd9iy(fls 42 :(fhsy:s is released from rest and undergz4uhqfftid29 (:(isy g2y s:loes 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 swings through its lowest point?

  04.41: A centripetal force o4j+kb7pg8 x0 zleqr 2q*6ibq of 5.0 newtons is applied to a rubber stopper moving at a constap7xeq+q qi6gbbl jk08*z2 4r ont 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 frictionlessezm2io c;(go h+ c8-m/arhy*w surface, 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 applied bz-2+ ca*(r/8 mcg emoywi;hho y the person to hold the mass stationary there?

  12.22: A girl swings a 4.0 kg mass with a constant +r/v int jzl:/i6yk/qg7v7yh 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 6q/r7ntz/i v7:l /ik gjvhy+ythe lowest point of the circle?

  14.23:Two small identical coins (labeled X andY) are at reston a hoa w6jzie/9,f* wlrk; mrizontal disk rotating at a constant rate about an axis perpendicular to the plane of the disk and through its centwm w*za /e9f;rljk,6ier. 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 em1rq7 xzm p16end 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 171xemmpqr 6zand 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 dfbbfl+g 94 o4kvjbs-+j8c7 ocircular motion as shown in the figure. The stri4v-d f j9 cl+4b +ksb87jofgbong to 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 11lx6svd 3 ue;i..0g is at rest 30.0 cm from a horizontal disk’s center. The disk starts to rotate from re;.elxvd 3u6 isst 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 9krl tho q6v(6m from the fixed center of a disk as shown in the figure. The disk starts rotating from rest with hk9q vl(rt6o6 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 initiacr+ rsup4s dc-:e.1rz1 wy7uchbli7 .l speed 17.0 m/s. The object’s speed increases uniformly until it has moved counterclockwise thro 7 ud l:b.rpz+ssw-4h1 cu. cic7yrre1ugh 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 inb7, ypp8dnp ,iitial speed 17.0 m/s. The object’s speed increase8yipp pdn7b ,,s 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 buc3)m: n,jqqzr4w ;o zfzket 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 rema3zw q: z;4fmn,q)rozjin 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.