95.02: An object shown in the acio.3jz zx wi47companying figure moves in uniform circular motion. Which arrow best d.zj iz34xw io7epicts the net force acting on the object at the instant shown?

  05.31: A child is belted into a Ferris Wheei8+1 flcr s-uzl seat that rotates counterclockwise at constant speed at an amusement park. At the location shown, whilrsz8+ fu1-ci ch 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 sk*heh3 d8 -wtrpeed in a counter- clockwise direction. Consider a time interval during which the particle moves alrhw-3ht *d8e kong 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 circular ow0b ju v0gmay-goax;.::/hwf(dj +kpath at constant speed in a counter- clockwise direction. Consider a time interval during which the particle moves a-u(gwb0:vyx; d+ m. kgjofo/0w:ah jalong 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 clockwi v8qeb6d9dr(gse with constant speed around the vertical circle shown. Which arrow best indicates the direction of the ob d9vge d(68qbrject’s instantaneous
acceleration at the point labeled X?

  12.11: A girl twirls a,*-b ljbnp0f jue s1h) small mass connected to the end of a string counterclockwise in a horizontal circle ab-* fjhl j,)s0 p1bnbueove 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 of the string?

  15.23: A car moves with constant speed around a horseshoe-shaped path as h2 1n(9za8otuxsxo) j.wc) eushown with the arrows in the figure. Which one of the follow 9tuxow)8 1ahn.(z2soujx) ec ing 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 with2lg*:w3dk gnh . hp1mo a simple pendulum that is released from the horizontal position at rest. At the moment shown in the3hoggpl1 n2kwdm .h :* 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 f;4ztxe ,e9:8 jh yx 4d,kprbderom the center of a rough turntable as the turntable rotates. The period of the turntable's rotation is 5.0 seconds. The coefficien :p;,rej9t 4kx,hx e 8edbyz4dt 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 nezcehb3p8oub om (7+a8cessary to keep a 1. 0 kg puck moving in a circle of radius 0.5 m on a hori c88 poh(bozue+m73ab zontal frictionless surface with a speed of 2.0 m/s?

  05.03: What is the centripetal acceleration of an object (mass = 50 r b8bht6a61x ig) on the end of an 80-cm string rotating at a constant t 8b6ixarh1b6 rate of 4 times a second?

  09.24: A point mass moves along a horizontal circular path of radius 0-q /h-:pun4v4x 5x xdkydeb,l .8m with a conq h-l4/dyekd :,-nxu bvpx5x4stant kinetic energy of 128J. What is the magnitude of the net force acting on the mass as it moves?

  96.24: A 2.0-kg ball is attached to a 0.80 m string and a wjyb.-k-bsor1a 5t0whirled in a horizontal circle at a cbyoasr kj5- . -wat1b0onstant 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 j h v 1,:vqozazg81921 kgzasdend of a rope, in a uniform circular motion. Which of the following statements is NOT to9h z qdj11:8vg aksg1,zav2zrue?

  00.19: An astronaut in an orbiting spuj0 -fnjx4 bj1ace craft attaches a mass m to a string and whirls it around in uniform circular motion. The radius of the circle isjn04j1b -fjx u 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 ;z6lrj+uc/n(4diqz kuntil the string of length L to which it is attached makes a 90- degree angle with the vertical. The mass is released from rest and swingsz6ck4i(j r;dz+ unql/ 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 to the right. svppxx6lsk ns 45y;(5Assume the car has speed v and the tops and bottoms of the hills have radius of curvature R. The driver of the car i5;(xyvs x6k4 snlp5pss most likely to feel weightless:

  17.10: A 2000 kg car moves over a hill at a constant speed of 12.r-4thp ,zb;ok3l wrjg4 yh(m.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 hm(-w3j k; tpol 44yzhr gb.r,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 vertical circle at constsfr/; l oia zfu(8+s5fant speed. The magnitude of the net force on tfo5 /+s fla;8u(frz sihe sphere

  11.47: A simple pendulum of lengthot-;y m wv.w78rur *zz Lhasa point mass M released from rest from the horizontal position shown. In the absence of air resistance and friction, the mass s.*7 w8ruo zvy-rt;zw mwings 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 str 7aixglv r;,.4t8jrvpba(d;b: wyw 2eing forms a simple pendulum. The mass is released from rest and undergoes simple h(wx;r dyw.ae4i ;:r7b bl2vtpg8aj, varmonic 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 centripetalj bvwh03 29x4; zbznmc force of 5.0 newtons is applied to a rubber stopper moving at a constant speed in a horizontal circle. If the same force is applied, but the radius is made smaller, what happenh;b293c xwvmj 4z0 znbs to the speed v, and the frequency f, of the stopper?

  05.28: A mass, M, is at rest on a frictionless surface5lf ns1p:m9jqbvqx)5) cv 9uu, 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 doufmquvx5c)9u1):n qs jl5 p9vbbled 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 vsix vx;jvc h,x 2k;fjk/de/ k395ahw mp//0vconstant speed of 3.24 m/s in a vertically-oriented circle of radius 0.75 m. vpvxx/;kkd9j2cxe0hi;5k hjfsm /3v a /w/v,What is the net force acting on the mass when it is at the lowest point of the circle?

  14.23:Two small identicap ;b4-p 63 uef.bxp v,)f kfbk8mfaet30i t5pcl coins (labeled X andY) are at reston a horizontal disk rotating at )f;p bx p,kb3t8 -b60tkci4pp3fm ee 5uafv.fa 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 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 strilo8m,q/z;wlce o kz u2 8hk;:cng 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 ;/wlmk h; uo,8qkcz ce8z 2lo: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 unifcmx y n 73pzhoh/2l6jalw2:4horm circular motion as shown in the figure. The string to which the massj6h p22xa3 /h cwmy h7llz4n:o 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 fy1m. ctw+nf7erom a horizontal disk’s center. The diskcf.+t ymenw17 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 difshwyamfs/-) )k .+nsstance R =1.75 m from the fixed center of a disk as shown in the figure. The disk starts rotatk+. -f /ays)fwmn)ssh ing 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 at the top, with initial speed 1pz .o. i0yxxr:7.0 m/s. The object’s speed increaipoxr x:yz..0ses 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 final speed of the object?

  16.40: An object moves /yz.(wsovqh,8a 8lycu q5utud*f(r 0 in a circle, starting at the top, with initial speed 17.0 m/s. The object’s speed increases uniformly until it has moved countercloyta,(r uhfylu (*qzs c8v/od.q05wu8ckwise 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 of a bucket. T4spa7 jnv+:u xhe 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 place in tnvs jp +xu4:a7he 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.