95.02: An object shown in the acy0u+b3x*sy gicompanying figure moves in uniform circular motion. Which arrow best depicts the net force acting ogib0u s *yxy3+n the object at the instant shown?

  05.31: A child is belteph; (-te+ai7do -.vchmgijx7d into a Ferris Wheel seat that rotates counterclockwise at consje ;-hh7+7t( gpcd.vaix- mo itant speed at 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 continuously moves in a circular path at constant s m77zv6cn14edylg(xb peed in a counter- clockwise direction. Consider a time interval during whic7 z (xc7nmedy416blv gh 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 velocity during this time interval?

  08.15: A particle continuously moves in a circular path at constant speen ;38,uampqdid ipri1upk8:7 d in a counter- clock,pu1i8dk 8ur;3i pnmap:qd7iwise 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 P.
What is the direction of the average acceleration during this time interval?

  15.07: An object moves clockwise with constant speed around the vmpuo3 :iq+ nb:ertical circle shown. Which arrow best indicates b+m:3uqip:o nthe 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 countercl./yzgx d0 py*k(z ral6ockwise in a horizontal circle above her head. The figure shows an outline of the mass’s path viewed f *l6x(.rzp yzkag0 d/yrom 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 pathgd msyhhs/c/e;;*j i) as shown with the arrow/)hj;se/hi cgs* m;dy s in the figure. Which 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 experime*5,)r n gdq.+atbbkrznt with a simple pendulum that is released from the horizontal position at rest. At the moment shown in the diagrqr)5 a+ r tdznb*,.kgbam 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 of an7 s(:r15qjq nj09xxwpij 8 xp rough turntable as the p(9 r0wn in8qjj7 x 5x:1sxpqjturntable 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 friction acting on the object?

  07.19: What net force is necessary to keep a 1. 0 kg punp7yqc ekow-q wh z/:otf++y 0o73iy:ck moving in a circle of radius 0.5 m on a horizontal frictionless surface with a ++k f/oyt cq30 e77nwywo o-izyqh :p:speed of 2.0 m/s?

  05.03: What is the centri2tb(z1 ghgvv 4*3au gvpetal acceleration of an object (mass = 50 g) on the end of an 80-cm string rotating at a constant rate oz4(bvh*uvg2 3tv1 g agf 4 times a second?

  09.24: A point mass moves along a horizontal circulk* p vyua1z3uivk j;x*+d2w /lar path of radius 0.8m with a constant kinetic energy of 128J. What is the magnitude of the net force act;xzk3pja2u y w v+*ld1i/ukv*ing on the mass as it moves?

  96.24: A 2.0-kg ball is attached to a 0.80 m string and whirled in a horizmr 7qhwqmbbz*os2(6w)c xp 79ontal circle at a constant speed of 6.0 m/s.)r po xc(q* s79bb2q w6zmwhm7 See figure to the right. The work done on the ball during each revolution is:

  99.22: A child whirls a ball at the end of a rope, in a uniform circuje r(.lnof. sfv,l,j7 lar motion. Which of the foll vln,( ,j7oels j.rff.owing statements is NOT true?

  00.19: An astronaut in an orbiting space cck2kam;-,olk raft attaches a mass m to a string and whirls it aroka;k 2- klmco,und 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 maintain uniform circular motion would be

  07.22: A mass m is pulled outward until the string of length L to+zt3rzluae3 kjjjl6 fzr +1acyv4o8 ),j:q7g which it is 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 +je,g3c4 +atl:z13)ljk zojv ru7fya8 j qz6r the bottom ofthe arc?

  94.15: A car is travelingug/l zqk6w g10(ybx 9d 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 ra6/ulq1g9zygb(kwd 0x dius of curvature R. The driver of the car is most likely to feel weightless:

  17.10: A 2000 kg car moves ove f(2c+6z40lw7zevh gk0 aysoz r a hill at a constant speed of 12.0 m/s. At the very top of the hill, the swhk7cavl z ysg04ez( f0z o26+hape 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 car?

  97.13: A small sphere is moving in a vertical circle at constant sp)zs;mhwv, rr v2y8bj6 eui +d9eed. The magnitude of the netvr zdhj8m+yie9v)r;uw s,2b6 force on the sphere

  11.47: A simple pendulum of length Lhasa point mass M releasei) qn:a-anukz9cf +yhsm*j+; 2+thje d 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 of the net force acting on the mass. Which one of the following choices describes the relationship amony af*+kanh+:9s)nqh +-;mej2tcj ui zg these forces when the mass swings at the bottom of the arc (point P)?

  16.32: A mass connected to sp g+/:9gks cda 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 (T), the gravitational force on the mass (W), and the net force acting on thegd/+sk :9gpsc 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 moving v dn6a;xparvg:qv1win 5,;/ q at a constant speed in a horizontal circle. Ifni;a v65x vgn;v,r aq/pdw1q: 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 af0; *weusfnr,(ign9 5le zc(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 masi(w ngc9euzf 0 5,;ear*nf(lss 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 speed of 3.24 m/s in a dht3)u3 koj*l (0aqiuv xfp-4b*bl 5nvertically-oriented circle of radius 0.75 m. What is the net force acting on the mass when it is at the lowest point of the circleqd *nl5-34t bl0b3 fo)vuk(iajhx*pu ?

  14.23:Two small identicz8kv(,k to 4 ao;pvx:oal coins (labeled X andY) are at reston a horizontal disk rotating at a constant rate about an axis perpendicular to the plane o k:ovav oz8,otpx(;k4f 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 string and moves aboutdrot3+)eg.xw m0qq ;v the string’s fixed end in a conical motion with a constant speeeg;.mqrq)xd 0t+ wov3 d 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 io eilv60wt 49sn the figure. The string to which the mass is attached has a length of L = 3.00 m and forms an vei4s otl096 wangle of $θ=50^{\circ}$with the vertical. What is the speed of the mass?

  13.23: A small object of mass 11.0gr6u4) q8f;t kmxdm (gr is at rest 30.0 cm from a horizontal disk’s center. The disk starts to rotate from rest about its center with a constant angular acceleration (xmf;rr 6tu)kq84 gmdof $4.50 rad/s^{2}$ . 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 wxxe e07ed0l b;uso4,u2 mav8y)ff0k is attached a distance R =1.75 m from the fixed center of a disk as shown in the figure. The di4v8u 07 e0b0def;oau,f2l )sykxwx mesk starts rotating 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, startin+msh6. l9; pxbhvi oq9jj x,.yg at the top, with initial speed 17.6j9p.ijxh+by xmq9s.l h, o v;0 m/s. The 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 final speed of the object?

  16.40: An object moves in a ciaaq*.b5 f)v *wbn+u tp0gcx2d 8ep c0o)hb:ghrcle, starting at the top, with initial speed 17.0 m/s. The object’s ceb00oabunc 2vf).a : p xb8d*gtwqphg*)h5+ 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 resz45;st8c. amm i az+irts at the 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 place in the bucket. a; +zmra 4c.tz58 iismWhen 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.