95.02: An object shown in the accompanying figure moves in uniform circ f.jh8bjwt;.+ tx3 r2k) cnaskular motion. Which arrow best depictswc b+ftjk3 j8 ;ra.)x2.kht ns the net force acting on the object at the instant shown?

  05.31: A child is belted into a Ferris Wheel seat that ro me+akxy) ajj*(r ; +wmooy4v1tates counterclockwise at constant speed at an amusement park. At the locat jv+x*a;owj)m1yokm yre+(4 aion 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 in a +4swqn;rv w7 z: hqni5counter- 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 h 5:q+7v rn; qwiwz4nscircle from Point P.
What is the direction of the average velocity during this time interval?

  08.15: A particle continuously moves in a circular paq ;0a6fede a89xr/avv th at constant speed in a counter- clockwise dvda 69/ r ;efxq0v8eaairection. 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 acceleration during this time interval?

  15.07: An object moves clockwise with constant speed ar.jp lw;ugj*n;dt1 )kr ound the vertical circle shown. Which arrow best indicates the direction of the objepr.n)jl *w g1u;;jdkt ct’s instantaneous
acceleration at the point labeled X?

  12.11: A girl twirls a small mass connected to the end of a string countercl8rky 6jia a2.. cg(bqxockwise in a horizontal circle above her head. The figure shows a jk. 28qb(cxyg. ria6 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 around a horseshoe-shaped patkn akjs(pke: 43y k52bh as shown with the arrows in the figure. Which one of the following choices best describes the direction of the average acceleration of the cars2pyak5:knkj( 3e4bk in traveling from Wto X?

  08.35: Astronauts on the Moon perform an experiment with a simple pentp lqc6pdw -hv,h l1(:dulum that is re q:(6h,- 1vcd lhtwpplleased from the 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 cenyf 81vs/zh(pxw6 e 2a*8itmanter 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. w 6 a2( ht/xma8znfps*18 eyivWhat is the magnitude of the force of friction acting on the object?

  07.19: What net force is necessa,1 vn)ms*f pffry to keep a 1. 0 kg puck moving in a circle of radius 0.5 m on a horizontal frictionless surface with a s fvm s)1,n*ffppeed of 2.0 m/s?

  05.03: What is the centripetal acceler cs4:yyer6yx 6ation of an object (mass = 50 g) on the end of an 80-cm string rotating at a constant rate of 44 :xysrcy 6e6y times a second?

  09.24: A point mass moves along a i )ff4*+xv3m;minv-z5o pf o hhorizontal circular path of radius 0.8m with a constant kinetic energy of 128J. What is the magnitude of the net v3m+h fo )ff5pizi4- o*xvm;n force acting on the mass as it moves?

  96.24: A 2.0-kg ball is attached to a 0.80 :jlz93dl ex8 p 8axor-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 opl8- ez:dxa j38r9 lxon the ball during each revolution is:

  99.22: A child whirls a bc/wg z+m dzq4ii/ t/8call at the end of a rope, in a uniform circular motion. Which of the folc/dzi8 t4m/i+g/ czwqlowing statements is NOT true?

  00.19: An astronaut in an orbiting space craft attaches a maswa8+fmv reube0*/tu ed85r g4s 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 strinaf m8 5deuv 8t0 4eeg+rr*/wubg 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 st 2;n9zl f(sxbaw/dij9ring of length L to which it is attached makes a 90- degree angle with twij;/ad9(szbxf 9 2nlhe 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 terraitee((0zjm 2 ean, see figure to the right. Assume the car has speed v and the tops and bottoms of the hills have radius of curvature R. The driver of(0j2tmeea (ez the car is most likely to feel weightless:

  17.10: A 2000 kg car moves o (ab)ys 9 swbjw7k/5vbver a hill 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 thbys(jbv/ )k7sbaw5w9e road on the car?

  97.13: A small sphere is moving in a vr/ le*bxhyta) jt v11,ertical circle at constant speed. The magnitude of the net t tal )/,h1*1byrev xjforce on the sphere

  11.47: A simple pendulum of length Lhasa poiv 7yjw23tw9gint 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 vg3jtwiy7 w92 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 zsncv s-igtpzw- *ia98u3-t3pendulum. The mass is released from rest a--c iaz-833nugziw 9t v s*ptsnd 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 swings through its lowest point?

  04.41: A centripetal force of 5.0 newtons is applied to a rubber stopper m14ztry4jc 9gk x /rl3xoving at a constant speed in a horizontal circle. If the same force is applied, but the radius is made smaller, what happens to xzlrck 3gx/ 1y r9tj44the speed v, and the frequency f, of the stopper?

  05.28: A mass, M, is at rest on a frictionlesl5 f0o+q5s3+q +jtbf hbw-b yss surface, connected to an ideal horizontal spring that is upstretched. A person extends the spring 30 cm from equilibr5bt 3jfh+q5w+0bsbolsf+- qy ium 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 constant speeit-e6ftwz,gqrs t av+.,+mj 7d 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 im+jt- tvt,e,+7f6 qzr.gsiawt is at the lowest point of the circle?

  14.23:Two small identical coins (labeled X andY) are at reston a 6 ig0/v bg70srrj-dcuhorizontal disk rotating at a constant rate about an axis perpendicular to the plar6g-vr7 i s0dj0uc/g bne 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 connectp*ct be7, +m 22prieyged to the end of string and moves about the string’s fixed end in a conical mot2+g e2rc7emppb ty ,*iion with 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 circular motion as shown i,czpy1hya ) r-n the figure. The string t p-ah,cry)y1 zo 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 cm from a horizont8k3bpxqx: :x( nw,5 lp50 ycjxvx c)blal disk’s center.)n:xxc8v wylbbk5x, x0( 3:xcjplq5p The disk starts to rotate 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 disd- gscef)9t ;ntance R =1.75 m from the fixed center of a disk as shown in the figure. The disk starts rotating from rest w )-tedgf9c n;sith 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 cino7a+s5m raz 0-a -ze9 mi- 8j*xftpzxrcle, starting at the top, with initial speed 17.0 m/s. The object’s speed increases upsof50zx- ai tz*j- are8 +am-m9nzx7niformly 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 5xek7t32d khe at the top, with initial speed 17.0 m/s. The object’s speed increases uniformly until it has movedk72xh3 dekt 5e 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 bloc 9dq;6, cvvkdbk rests at the bottom of a bucket. The bucket is spun in a vertical circle of radius L by a rope. When thevc; 96q d,bvdk 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.