95.02: An object shown in the accompanyhl2k3s21y qc jing figure moves in uniform circular motion. Which arrow best depicts the net force acting on the obje 13k jcylq2hs2ct at the instant shown?

  05.31: A child is belted into a Ferris Wheel seat that rotates countercloc; py 57uvdn/rckwise acnp 57d; uvy/rt constant speed 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 amj5k/b a)vbt8t gby d3al6(v7t constant speed in a cb)6v3 mb dyjv/ 5k7tb (g8atalounter- clockwise 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 velocity during this time interval?

  08.15: A particle continuously moves in a c8j j)cxa- h uzci3tqnp) (q1+hircular path at constant speed in a counter- clockwise direction. Consider a time interval during which the particle moves along this circular path from point P8c ajhcj))zp u-1 +qnix (3thq 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 s,htn9tiad6 p*iu;u9): tnfdx peed around the vertical circle shown. Which arrow best indicates the direction of the object’s ix;iu 9diht:,nftn*u9da 6pt )nstantaneous
acceleration at the point labeled X?

  12.11: A girl twirls a small mass conn+ ajitz28qmlg5ydbdq n:3 q bq6of ):(ected 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 through the point labeled P in the figure, at which lettered point on the path should she let go on5:i 8qy+ m )bbq2oj:azfd 6dq3(gqtlf the string?

  15.23: A car moves with constant speed around a horseshoe-shaped path as show)+8z as(oyb4: h1 b dv)q;ibbrjv+ zrun with the arr:doz(hv)abu41b+y )jiv8br; bs + qrzows in the figure. 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 to-gj)89mulytpuj,e0 x h, l5f he Moon perform an experiment with a simple pendulum that is released from the horizontal position at rest. At the moment shown in the diagram with -lh5gf),o e0u y8tujp,xl9mj $0^{\circ} < \theta < 90^{\circ}$ , 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 thset9p 7d,n9tp5.rw1ya6 kfp s87 qlxae center of a rough turntable as the turntable rotates. The period of the turntable,t xr.1w7 tpks 67pe sad9ypafql89 5n'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. 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 :ahk + zxw,*z*;fon pnd63motgl/px+ a circle of radius 0.5 m on a horizontal fricx+gntl*odp3mhxw p/+ nfzak6o: *,;ztionless surface with a speed of 2.0 m/s?

  05.03: What is the centripetal acceleration of an objeo/2j7yr u /-evucs(rsct (mass = 50 g) on the end of an 80-cm string rotating at a constant rju vc2/7ersro y/-(su ate of 4 times a second?

  09.24: A point mass moves along a horizontal circular path o quw(327(yps lq kl f)75qpzqv p1y.jnf radius 0.8m with a constant kinetic energy of 128J. What is tsn7 pl3q2(j )yqq.zyf( qw1klvp 5p7u he magnitude of the net force acting on the mass as it moves?

  96.24: A 2.0-kg ball is attached to a 0.82r kzwigsb*9 20 m string and whirled in a horizontal circle at a c2rz92*kw sbi gonstant speed 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 end of a rope, in a i ;-vlvy 5 nrehl/7bi/tb/q 0iuniform circular motion. Which of the following statements is Ne/in7lbi0b vl /hriy;q /5-v tOT true?

  00.19: An astronaut in an orbiting space craft attachej mh vng4gl9 76kv8 kg7rrjaqsp 72n4jjo0a34s a mass m to a string and whv4aj87497 h2ak n 4gg3 jo kjrs0lj7qn6mvrgpirls 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 ;s*l)x e o 2viijy.q-yL to which it is atse*iy iql)vj x y2-;.otached 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 bottom ofthe arc?

  94.15: A car is traveling on a road in hilly terrain, see figure t7hj a+9za uz b(jc+.dje1sbw ,o the right. Assume the car has speed v and the tops and bottoms of the hills ab1zs dz (+7bu,+h.jw 9cj aejhave 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 speed of .x;zm+ch /itmac 5uo3 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 the upward force exerted a.5t/ ciuhczxmm; 3o+by the road on the car?

  97.13: A small sphere is moving in a vertical circ* cf(wonm)cy.le at constant speed. The magnitude of the net fcm)(*wfcn.y oorce on the sphere

  11.47: A simple pendulum of length Lhaq q9xs)f7h1n ysa point mass M released 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 forces when the mass swings at th n y17hqq9sfx)e bottom of the arc (point P)?

  16.32: A mass connected to a string forms a simple pendulum. The mass3 h0 9l-hfh7;c( qjhwtf4ufhs is released from rest and undergoes simple harmonic motion. Which one of the following choice;h043j hhh- hq 7(wsf lt9cffus 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 5.0 newtons is apsn06fbv*t z mbi-b2s4plied to a rubber stopper moving at a constant speez2 b6ssv nbm4-bf*i0td 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 frictionless surface, connected to an +(pd9yqt3qll9yf 2 x hideal 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 equili9d9( hlqq+xy 3p2lyt fbrium 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 w8v98/d9c fc0ig;an ( kjpyzoxith 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 pointa 0dj 9o xv 8iczc;pyfk(89g/n of the circle?

  14.23:Two small identical coins (labeled X7p nv0 .3koowg andY) are at reston a horizontal disk rotating at a constant rate about an axis perpendicular to the plane of the disk and through its center. The distance of the coins from the center of disk is reln0 o pw73okgv.ated 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 thc/s1cbm3 lsl q5 x.*bce end of string and moves about the string’s fixed end in a conical motion wi s1 lcc5.sqcl*mb/3 bxth a constant speed 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 circasj :c( jqwf3 zu*e /-1e1ayrgas-1gq ular motion as shown in the figure. The string to which *f- e a3ujqag(je/ayz-cs1r1s1q g:wthe 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 cm from a horizont )g,+0s:lz fw,3q9lnftlufkr al disk’s center. The disk starts to rotate from rest about its centez,90w)kr,lq lf:n+flgs t3uf r 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 fn1u:ym; 8g(xtyt v7 jmrom the fixed center of a disk as shown in the figure. The disk87y :m(mt xtg;u j1nvy 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 a circle, starting at19hdd, tosy qf)6/e: dhrut6u the top, with initial speed 17.0 m/s. The object’s speed increases unif yos1 th)q:uer69dhd/ 6u tdf,ormly 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, withuwua 8 x116hickwc3+c initial speed 17.0 m/s. The object’s speed increases uniformly until it has moved counterclockwise through an au8w +wki 31c6hcc x1uangle 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. y8);5o ds7erl3 xjkz lThe bucket is spun in a vertical cklsd8er xzy oj75l ;3)ircle 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 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.