95.02: An object shown in the accompanying figure hmvtp,37 lkp te1vr;; moves in uniform circular motion. Which arrow best dem,te rvkv3lp;p 17ht ;picts the net force acting on the object at the instant shown?

  05.31: A child is belted into a Ferris W h*o.)* qseiqb 7h5ckqj6 vg;wheel seat that rotates counterclockwise at constant speed at an amusement park. At the location shown, which direction best represents the total force exerted on the child by the seac.h;keq qiq5* s)j*vg7 b w6hot and belt?

  08.14: A particle continuously moves in a circular path at constant speed in a e-hn: f)k hm/ccounter- clockwise direction. Consider a time interval during which the particle moves along this circular path from point P to pointche: f/)nkh-m 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 p9 l l b 5a*h3gn3mxxv/01nw+wv hr3jzuath 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. Point Q is exactly half-way around the circle from Point r/h33+ m1l*zlwx3uw59 j vnhn0xg avbP.
What is the direction of the average acceleration during this time interval?

  15.07: An object moves clockwise with constant5)ncsqh,l87ssn lft-p 25. 7igyf fcw speed around the vertical circle shown. Whin5i7f pts8.gn y2lw 75 s-flscc,)hqfch 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 of a string counterclo vgmst.aph6zdb )+,v4 ckwise in a horizontal circle above her head. The figure smsb)d . gptahz4,v +6vhows 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 wsqr4r6o9 kxt2 ith constant 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 accetorqrsx64k 29leration of the car in traveling from Wto X?

  08.35: Astronauts on the Moon perform an experiment with a simple pendulumw+v0wx zt3jyg 4y.uo; that is released from the horizontal poo x0tw43;gwjuzvy .+y sition 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 oz 1s 89mqee;sk/x6aa abject 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 static friction is 0.80. What is the magnitude of the fo1 a8k;/69sax qzseea mrce of friction acting on the object?

  07.19: What net force-czw(r2/ ch8b g j*av7dnisp* is necessary to keep a 1. 0 kg puck moving in a circle of radius 0.5 m on a horizontal frictionless surface with a speed of 2.0 m /cn bi8*vpr(j 2shwa7-c*zdg/s?

  05.03: What is the centripetal aro(*)bmlvn; e cceleration of an object (mass = 50 g) on the end of an 80-cm string rotating at a consbn v(omrl* ;e)tant rate of 4 times a second?

  09.24: A point mass moves along a horizontal circulwz5sj sy z,rfs6-9 h t-tdj6tgw7d n1*ar path of radius 0.8m with a constant kinetic energy o tj* 75nz fzds6y -wrsdj1h 6tw9-,gstf 128J. What is the magnitude of the net force acting on the mass as it moves?

  96.24: A 2.0-kg ball is atta/x:abp 4xq4 idched 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 right. The work done on the iqx4: pxa/db 4ball during each revolution is:

  99.22: A child whirls a ball at theqpp.1nr ,uf 8q1rq.zm end of a rope, in a uniform circular motion. 8f ,rq1 nmp. p.urqq1zWhich of the following statements is NOT true?

  00.19: An astronaut in an orbiting space craft attaches a mass m to a sz h c3ww (qwo4ky j0cap33a-j+)w) spptring and whirls it around in uniform circular motion. The radius of the circp3chwks p)-4pqc3)a +( awyj3 jw0woz le 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 which it is akbvq p 5rt,+ y :6fc f6qt5abtnk, *q;*wznmr5ttached makes a 90- degree angle with the vertical. The mass is released from rest and swings through a circular arc. What is the tens;cn,vq y,*r6 b*55tq prnt k qfza:f6k+5mb twion in the string when the mass swings through the bottom ofthe arc?

  94.15: A car is traveling on a road in hilly terrain 9pe9n/mh 7q/9 3ajaz*hywmy h, see figure to the right. Assume the car has speed v and the tops and bottoms of the9ny/j/ h 9a pmemy3zqhwh79 *a 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 o7dk r/9sii, nhill at a constant speed 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 indicated in the figure. Which one of the following choices best represents the magnitude of the upward force exerted by the road on the ir9d nio,k7s/car?

  97.13: A small sphere is moving in a vertical circle at constant speed. The mag,x yz-9jl)aqm nitude of the net force ozm)9qyl-ja,x n the sphere

  11.47: A simple pendulum of length Lhasa point mass;ogby.fjl : 6,qm)jf s M released from rest from the horizontal position shown. In the absence of air resistance and fr sgyf;6 b:j)j fo,mq.liction, 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 the bottom of the arc (point P)?

  16.32: A mass connected to a string forms a simple pendulum bq1a;n;a )b+ud) iq)uj,nxxto*/ bf w. The mass is released from rest and undergoes simple harmonic motion. Which one of the foi qx xnj;) n1 b bau;/,wqf)dut*+a)obllowing 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 of 5.0 newtons is applied to b*:cs2foem; pa rubber stopper moving at a constant speed in a horizontal circle. If the same forcb2 c*so:;pemf e 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 suxnfv;dd- t0dyg:mj: :rface, connected to an ideal horizontal spring that is upstretched. A person extends the spring dv0f::- x: jmgtdy;nd30 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 by the person to hold the mass stationary there?

  12.22: A girl swings a 4.0 kg mass with agw6i gcgb*2 ryn7ai i15gt5:l constant speed of 3.24 m/s in a vertically-orienteg g25ctb gi*1la756gy: iwr ind circle of radius 0.75 m. What is the net force acting on the mass when it is at the lowest point of the circle?

  14.23:Two small iden1ow sk(sjve5 )4tcm 5ytical coins (labeled X 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 from5kv w )jce s14y5os(mt 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 a57 +pyjeyi0a dnd 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 mdy i7ea+0 yjp5 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 unif7e(4lluyh* xlh7daa+ orm circular motion as shown in the figure. The string to which the mass is attached has a lyl4a(h 7eldl*+ah7u xength 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 d8wx8 d+8 tsbu11.0g is at rest 30.0 cm from a horizontal disk’s center. The disk starts to rotate f+dt88bw du s8xrom 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 = 2.0qfv1j)i-2- . v/5lbqw xa 66rifkyv zn kg is attached a distance 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 acceleratryf6wx)2-6 vqbf jzki-5/v1 .nqlv iaion $α =5.00 rad/s^{2}$ 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, sta2 t cv;yufafk1rchwz6( )w) u,rting at the top, with initial speed 17.0 m/s. The object’s speed increases uniformly un1 a cwu;, t6z)wvfrkyf )2hu(ctil 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 atpjr (gm9m 6c aa/pe(+o the top, with initial speed 17.0 m/s. The object’s speed increases uniformly until it has moved counterclockwis(app6j 9c oe (m/ar+gme 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 thyfwc1ww9,hxt )v( ; hge 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 fast enough for the block to remain in pla ,vhy)w tw(;hg9w xfc1ce 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.