95.02: An object shown in the accompanying figuraq mbo6-pt mhrp h8,7buc+,-oe moves in uniform circular motion. Which arrow best 7qapu8mb pho-c6rmt oh+,,-b depicts the net force acting on the object at the instant shown?

  05.31: A child is belted into a ad86xag 8d,ek Ferris Wheel seat that rotates counterclockwise at constant speed at an amusement park. At the location shown, which direction best represents the tx88,ad agd 6keotal force exerted on the child by the seat and belt?

  08.14: A particle co(b rsv4 :za dq*p *udp+f9)x 1f1qwkllntinuously moves in a circular path at constant speed in a counter-rlavq91 wlq)4xpfbz*p:(d+ fu* k1sd 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 circle from Point P.
What is the direction of the average velocity during this time interval?

  08.15: A particle cocy v7-rb-p0: fqi.q1w (p9xmx f: nzdoj5(szpntinuously moves in a circular path at constant speed in a counte.dxrfn- o pz s9pfx:7iyqzc15 w pq:(j0-(bmv r- 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 circle from Point P.
What is the direction of the average acceleration during this time interval?

  15.07: An object movehi*h efqt z3(jx1:dcf4 38zdis clockwise with constant speed around the vertical circle shown. Which arrow best indicates the direction of the object’s inst*hii3hf3zf x:dj14qe(z c 8dtantaneous
acceleration at the point labeled X?

  12.11: A girl twirls a small mass connected to the end of a string coun9 ,q0ght ic)koxu7fpi (0r hf*terclockwise in a horizontal circle above her head. The figure shows an outline of the mass’s path viewed from above the twirling mass. If the girl needs the mass t0uri xpg 0q( *9i k7)cf,fthhoo 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 shown e1h9qg a 5dzl7-tprne.1rz1twith the arrows in the figure. Which one of the following choices best describes the direction of the average accele1 .qr-ldh51nzgee9z atpr71t ration of the car in traveling from Wto X?

  08.35: Astronauts on the Moohq204t yvipe 1n perform an experiment with a simple pendulum that is released from the horizontal position at rest. At the ih40 yeptv1q2moment 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-lik tpwpc-2v0o8*k bkg 9ye object rests 2.0m from the center 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. What is the magnitude of the force ofv0ty w892bgck -okp*p friction acting on the object?

  07.19: What net force is necessary to keep a 1. 0 )+: h ):vlgotkw+d46m xvmje fkg puck moving in a circle of radius 0.5 m on a horizontal frictionless surface with a speedf +4gvw+jxkotlh)vdm 6 :me:) of 2.0 m/s?

  05.03: What is the centripetal acceler. ca5q5ufw bz4y:tb2bd 7qs qtx ,-8rpation of an object (mass = 50 g) on the end of an 80-cm string rotating at a constbsq4-bxp52 fwc try 8:q,7aq5ubzt .dant rate of 4 times a second?

  09.24: A point mass moves along a horizontal91fjgpgzas5 - circular path of radius 0.8m with a constant kinetic energy of 128J. Whszp5 g1-g a9jfat 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 whirled in a horizontal 2m7b ya3a16n6peabhvcircle at a constant speed3ye 72h6b apava6bnm1 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 end of a rope, in a uniform cim(m:rykpa y2+zwoy 0ckj) 7xu,2q je (rcular motion. Which of t pyj+k2zeo(702y:ykqm raw)jm(cx, u he following statements is NOT true?

  00.19: An astronaut in an orbiting space craft attaches a massa1kejuv:)on ; fo1yh 70dw(5ejh 5met 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 kn f0)e emu yj o51owav(dh17ht5 j:;estring 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 stringzfa8 -v d3,g)i wq:i .jpkxjz0 of length L to 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 stringvpj8- dgx: k iz.3az fq,)0ijw when the mass swings through the bottom ofthe arc?

  94.15: A car is traveling on a road in hilly terrain, see fimgl/- b*r*n1p hewb ti+t, :mdgure to the right. Assume the car has speed v and the tops an1me*p d/r:wghb +bl*-tt ,mind 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 constant8vc 11klb 2yzj speed of 12.0 m/s. At the verzj 1bl2c vy1k8y 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 the road on the car?

  97.13: A small sphere is moving in a vertical circle at constant speed. The vtt83ko( c/rxow hz2b*68fp ymagnitude of the netx*hf2 86v 3octpzwrb 8 (toyk/ force on the sphere

  11.47: A simple pendulum of length Lhasa point mass M relelrkcx*k 5exc(6pk p8*ased 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 m pk(lk68 p5*xkcr*exc agnitude 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 pendulum. The ml,)kbe* p(s*hy3n44a/hks a zh e0aek ass is released from rest and undergoes simple harmonic motion. Which one of the following chon(s3besa)4ak0* lpk/kheyh *4, ae zh ices 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 isb/51 nz4i27 1beg fm0fq mbhd n8fqdl1 applied to a rubber stopper moving at a constant speed in a horizontal circle. If the same force is applied, but the radiusq1ehd i f8qbd0bn 51gzf fm4m/71bnl2 is made smaller, what happens to the speed v, and the frequency f, of the stopper?

  05.28: A mass, M, is at re9, m9h l5ubmdust on a frictionless surface, connected to an ideal horizontal spring tm du9l9buhm,5 hat 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 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 spc-uq-q9g0 b(a yepq7v eed 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 it is at the lowest poinq9c7p eyb-va-(q u0qgt of the circle?

  14.23:Two small identical coins (labeled X andxh );n(h5ki92hzn jv efx: nn5Y) are at reston a horizontal disk rotating at a constant rate about an 5nhzf hv2n j;:9n)xhxe( nk5i 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 .d/i(p4 ,qo;bnc ekmaconnected 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 strie. i (od/,mpn kcb;a4qng 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 hcpp2y61/z4/vnc g .el1wt 6 exe(qqdin the figure. The string to which the mass is attached has a length of L = 3.00 m and form1zg2(4c/ce.6n6lq xepd q 1yw/ ephtvs 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 horizoncr(( fu(3 oc2 xej,kjje 6iw*otal disk’s center. The disk starts to rotate from rest rxuc*6e c ( k(, 2of(3eiojwjjabout 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 attacw hvv gk:v g;ufg0696nhed a distance R =1.75 m from the fixed center of a disk as shown in the figure. The diu9 0h;v:k6gw nv fg6vgsk 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, starting at the top, witjn cm )fz5d-79d en4bjh initial speed 17.0 m/s. The object’s speed increases uniformly until i7dj b-) c5znf4d m9nejt 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 at the top, with initideqn)hojt+39 2h n zq6al speed 17.0 m/s. The object’s speed increases uniformly until it hasehh6d n)zn 2q j+qt39o 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/.fdnimni 82t w )qrf9 the bottom of a bucket. The bucket is spun in a vertic/2dqinn9 w) ifm 8rf.tal 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. 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.