95.02: An object shown in the accompanying figure moves in unifdt l*93fg qsu;/vqwl (orm circular motion. Which arrowf sqgt/9* dqulwv3;(l best depicts the net force acting on the object at the instant shown?

  05.31: A child is belted into a Ferris Wheel seat that rotates counterclozjzbh nnp;f ej 90)f26ckwise at constant speed a620ezn) f j9bj;hfpz nt 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 contzry 0 k;7n)pbd/j 7gopinuously moves in a circular path at constant speed in a counter- clockwise direction. Consider a time interval during which the particle moves along this circular pjykb77/0r gz;d n)op 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 sya5wmd*pfbu -7f 4 0nbpeed in a counter- clockwise direction. Consider a time interval during which the particle moves along this circulara5yu0f pwn b4-mbdf7 * 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 c / ls7 wjl4q/1af35v ngfb8srgonstant speed around the vertical circle shown. Which arrow best indicates the dir sf1 n/s8blvwja7ggr3flq5/ 4ection of the object’s instantaneous
acceleration at the point labeled X?

  12.11: A girl twirls;hk pd5v/i8y/ esx q5 og;qnm/ a small mass connected to the end of a string counterclockwise in a horizontal circle above her head. The figure shows s;q5k/on/y /dxqv8e;g pm5 hian 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-shaperbctrry-1l 5 1ce.6yqd path as shown with the arrows in the figure. Whq5.rc1rlt- 6ry e yb1cich 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 the Moon perform an experiment ( :z;mdll8spa + uidj9iq6 pt5with a simple pendulum that is released from the horizi+(; qsl t5l pip98:dz6dju amontal 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 center gj9*irnk xv.3xk bz7 9of 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 force of frictio 7z9k.x g vni93bxrjk*n acting on the object?

  07.19: What net force is necessary to keep a dwg-dm-vd2f,g+j9 xsw7 p+xk 1. 0 kg puck moving in a circle of radius 0.5 m on xdwfpgwg2 - +sdmd-j k7,+v9 xa horizontal frictionless surface with a speed of 2.0 m/s?

  05.03: What is the centripetal acceleration of an object (mass = 50 g) heclb/6la r wye)(u,fqa5*x /on the end of an 80-cm string rotating at a constant rate of 4be wy r/q6xa*,ec5ua)flh /(l times a second?

  09.24: A point mass moves along a horizontal circular path of radius u86uy8 th/nlmdm.7 t m0.8m with a constant kinetic energy of 128Jmut t/dl8hu 8nmm y6.7. What is the magnitude of the net force acting on the mass as it moves?

  96.24: A 2.0-kg ballg z:qda xbg i e3ahsu;a+e(+ez7--a2h is attached 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 ball durina 7 e+z(+su: 2bh-zg iega3xda qha;-eg each revolution is:

  99.22: A child whirls a ball at s)5v)nf74/bl2 j xmj vibtdf( the end of a rope, in a uniform circular motion. Which of the following statements isxjjn)mldf)f2v5/i 47 vsb (bt NOT true?

  00.19: An astronaut inv2c7m4.fq wfhm1*j bne5exn9 an orbiting space craft attaches 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 tension required to maintev f*c.f j7hbmnw29qn15x m4eain uniform circular motion would be

  07.22: A mass m is pulmhhk w6*l *rh, m*/pidled outward until the string of length L to which it is attached makes a 90- degree angle with the vertical. The mas*hip ,kh*ldhm wm */6rs 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 travejz hjyh y2/e+ wz*tw/.oe7hp4ling on a road in hilly terrain, 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 owetz j+ y 47j/w/yhhhezo*.p2f the car is most likely to feel weightless:

  17.10: A 2000 kg car moves over a hill at a con q4cpb30 e/c3al+ofi nsh9+me stant speed of 12.0 m/s. At the very top of the hill, the shape sq/lmpca +foe93bi+0 4e3 chnof 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 car?

  97.13: A small sphere is moving in a verticalnq49if0fvdxe )q4 7f4p;s pgb circle at constant speed. The magnitude of the x b nq4 4q7e4 )ff;pfp0vgsid9net force on the sphere

  11.47: A simple pendulum of length Lhasa point mass M remvy ic, ifw*;b fxi1e: s721cnleased 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 t cf*sy ,xmini1 v2f7:cw;e1ib he 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 fr:k j o-ju*l-torms 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 (T), the grat rk:ujl*o--j vitational 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 ahx (6-9uhygpp rubber stopper moving at a constant speed in a horizontal circle. If the same force is applied, but the radius is made smaller, what happens ux9 hpyghp(-6 to the speed v, and the frequency f, of the stopper?

  05.28: A mass, M, is at rest 7peq, k8ixnr(1xmi h5on a frictionless 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 necessarrh7qmeii n( x,p k58x1y force applied by the person to hold the mass stationary there?

  12.22: A girl swings a 4.0 kg mass dckn8a r3o 2jyvp o(k1l4fozq,v/ k;( with 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 maronoy3/vzf , 1q4k (lvok82c ;dj( pkass when it is at the lowest point of the circle?

  14.23:Two small identical coins je )qcpvpq1bd3. +1(wj t,g ob(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 disgevoj c d1+b(wtqbpj13. ,q)ptance 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 connecten-1 -a2my6bhx07gu9 s ykvpntd to the end 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 a 1knutn- say2-067 p9gxvmhyb nd 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 afom1;ok,x*d-j7 /kmos)n hy gd (nu0ls shown in the figure. The string to which the mass is attached has a length of L = 3.00 m 1 fluds*7(nojg kn/xomm yk0dh-,;)oand 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 horizontal disk’s utt/,gmb0 jzn* bc8 7nwr+v 8enj0v8 r+cgmebwt un*,7z8bt / center. 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 atgx qjl*:4 pb8rtached 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 angj*l48brx:q p gular 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 topfe(/u8mc ;szirg;kr9 , with initial speed 17.0 m/s. The object’s speed increases uniformly until it has moved(kcr9;;ezsr /8mgf ui 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 9u k5lawd *3aicircle, starting at the top, with initial speed 17.0 m/s. T95lu3w daaki* he 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 bottom ofcuzp7 e hcxp9gp*s*,+ a bucket. The bucket is spun in a vertical circle of radius L by a rope. When the bucket reaches the highest point in it*h*p,xs e+gcp97p czus 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.