95.02: An object shown in the acc, j)lnw fwr/n.f+0ic9m v/k/auzu8zsompanying figure moves in uniform circular motion. Which arrow best dewm/j) r i9/fzlna, zkfcu/u.+8wsvn0 picts the net force acting on the object at the instant shown?

  05.31: A child is belted into a Ferln a2krq6gd3c2( v+ m4ut+wox ris Wheel seat that rotates counterclockwise at constant speed at an amusement park. At the location shown, w3cl2mw utodn 6 ++gakxv2q(4 rhich 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 ia- qdzf41s54wacuy0 b 1zccy 4n 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 cir4 ub14za cw-c5yqc4y1d 0sa fzcle from Point P.
What is the direction of the average velocity during this time interval?

  08.15: A particle continuou hvgco0.h,9o usly moves in a circular path at constant speed in a counter- clockwise direction. Consider a time interval during which the particle moves along thisuc0go9 h.vo ,h 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 constgkc c8; 9j p+shjz;m-yant speed around the vertical circle shown. Whichc9 zphs8jy; gkc -;mj+ 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/d,gi xgu/z g9 string counterclockwise in a horizontal circle above her head. The fgzxgi//9du, gigure 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 speedsvuw;-g;ex fd fq1qw*c71a *t 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 acceleration of the car in travelingwf*a-;fd11 7 uwqxcteg sq*;v from Wto X?

  08.35: Astronauts on the Moon perform an experiment with a simple op/:jd: 4i8nx *t pbh0vv cu)kpendulum that is released from the horizontal posi0 iv)d 84x:pbpnvuoc:* /jkthtion 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 centokjm34 +)hb yher of a rough turntable as the turntable rotates. The period of the turntable's rotation is 5.0 seconds. The coefficient of kinetic frjk+ yb4moh)3hiction 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 movingfn/ ll.xitcsau2:;l w7lxj f)u3 pa66 in a circle of radius 0.5 m on a horizontal frictionless surface with a spc.6taxl3liu 6 )al n /upjs7f2x:w;fl eed of 2.0 m/s?

  05.03: What is the cu+sk8h a;ai ,eentripetal acceleration of an object (mass = 50 g) on the end of an 80-cm string rotating at a constant rate of 4 times a ia8h+,sku a e;second?

  09.24: A point mass moves along a horizontal circular path of radius ci93 yw1dhj5 )j2by+m ) kojrg0.8m with a constant kinetic energy of 128J. What is the magnitude of the iw92djyrj c ) y)h 31bmj+5kgonet force acting on the mass as it moves?

  96.24: A 2.0-kg ballpgk-2 ko sl*m t w) sq aw1,b/46igsqwxn07n2w is attached to a 0.80 m string and whirled in a horizontal circle at a constant speed of sn x/wsqn7wbg-41w0wa 6t ig2, omkl*q2p )sk6.0 m/s. See figure to the right. The work done on the ball during each revolution is:

  99.22: A child whirls a barlrvgpe;4- 5w 9e1upm ll at the end of a rope, in a uniform circular motion. Whic-r e;pe1 u54v pl9mwrgh of the following statements is NOT true?

  00.19: An astronaut in an orbiting space craft u d.x -fm.o*fvattaches 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, andmo..d *vffx -u 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 iokjfx e5y9 v;na ,f2m5s 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 boj9x 2nky5 maff;v,5e ottom ofthe arc?

  94.15: A car is traveling on a road in hilly t*r2.rv tmchrfxl7hxr ij715,j6 ga1 d errain, see figure to the right. Assume the car has speed v and the tops 2chr67 jjm.7gai* 1t1vr xx,ldfhr5r 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 speed of 12.0 m/s. Az.jm1wl s/ssyph ,:2 ot 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 b2mjwo:.sz l/ssyp ,h1 y the road on the car?

  97.13: A small sphere is moving in a vertical circle at-qxu2 w(si+hbm g+q y)) ktu6m constant speed. The magnitude of6sh (xy+qb+- gu) u2)itmmwqk the net force on the sphere

  11.47: A simple pendulum of length Lhasa point mass M released fromnii4 c9oes7+ ;uus7f v 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 descri9+nc4;ss iuu7vef7io bes the relationship among these forces when the mass swings at the bottom of the arc (point P)?

  16.32: A mass connecy om6/t)b(smr +7n731 dipbre4hbsck ted to a string 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 by/7+krb1) 6rp(cm t3sm7 db ie s4noh(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 e,)()txgw oo tof 5.0 newtons is applied to a rubber stopper moving at a constant speed in a horottgw ))exo( ,izontal 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 s z (e,jxs3d75u lqdaoh (x q*xg76jp6wurface, connected to an ideal horizontal spring that is upstretche xujsqoa( 76xe , ldzdx*w73h6( gjqp5d. 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 by the person to hold the mass stationary there?

  12.22: A girl swings a 4.0 kg mass with a constan ( myt v6be3j2iuxsx,2t 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 26i e 3yx,ju( m2xvsbtwhen it is at the lowest point of the circle?

  14.23:Two small identical coins (labelylk v,hhiebu80 /0s-fed 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 v/f0iuhbk08l -yse ,h. 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 strilwl l;k8v/-s2. cbdd +)zojzgng 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.sd; +bgzl- )clzlv k 8dw/o2j 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 unizu.jg2dt; 8a.su md 6-u ov/ctform circular motion as shown in the figure. The string to which the mass is attached has a length of L = 3.00 m and u8od-; st.26. tvu/azmu jdgcforms 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)4eqj7hcts23a /oxby2l dz, d cm from a horizontal disk’s center. The disk starts to qh jdds /2 aoz37yct2lxe,) 4brotate 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 attach rlld3wzj,do98k77c wed 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 acz7 8dw7,3rklc dl9woj celeration $α =5.00 rad/s^{2}$ 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 cirx cah3w*g .c ur-b;p3rc):v lycle, starting at the top, with initial speed 17.0 m/s. The object’s speed increases uniformly until it has moved c:hv;b)ulp3r3.g c-a* wryxc 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 (gzkdicj 8j4 ,circle, starting at the top, with initial speed 17.0 m/s. Th4j8i(k,zj g dce 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 time for this motion?

  17.38: A small 2.0 kg block rests at the botlndhdeq;eg *g+j )77rp/ ls w: 2d9mdctom 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 jg2cs: ;*dn ep+d77/m lw9 hlgd) dqerits 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.