95.02: An object shown in the accompanying figure moves b/);cl,o)do dd et/oyjga(c/:.kjq o e4vw (uin uniform circular motion. Which arro)jckvoed /:)yd4bog.(wa oq deo ( tlcj,u;//w 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 6h e.h4c;tdymrotates counterclockwise at constant speed at an amusement park. At the location shown, which direction best representye .dth6;cm h4s the total force exerted on the child by the seat and belt?

  08.14: A particle contiis l,zggvf0e olyzfxi48 941- nuously moves in a circular path at constant speed in a counter- clockwise direction. Coz, goli4-fyv lsfx8egz14 90insider 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 continuously moves in a circular pium j31o2 ns4 vkj*zs(ath at constant speed in a counter- clockwise direction. Consider a time interval during which the particle moves a js3z1(n2 vkosi4* jmulong 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 8pj0idj 3 :-atxd; gzfvertical circle sh8px-j:0;dg tzjfi3a down. Which arrow best indicates the direction of the object’s instantaneous
acceleration at the point labeled X?

  12.11: A girl twirls a small mass connected to the end hpyc 93 3n0z5 )uf.-tjcftwvhof a string counterclockwise in a horizontal circle above her head. The figure shows an outline of the mass’s path viewed from above the wn)c9-0jc fy3 u . t5thzp3vhftwirling 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 pajt*:f,9 2tgfkzcj 83*baffnz th as shown with the arrows in the figure. Which one of the following choices best describes the direction of the average acceleration of the car in travez9z n*g: f 3f*t8ftj,2f kjbcaling from Wto X?

  08.35: Astronauts on the Moon perform an expmbxf-6kmjkuz 7, j5 o7eriment with a simple pendulum that is released from the horizontal position at rest. At the moment sj, kxo5kf6u jb -7mm7zhown 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 fromb oxfpq(3,ux * 7eez9l 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 betweenqlpexu, 7e 9fbox( z3* 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 puck moving wu4.,z zc(pm.d gglz7in a circle of radius 0.5 m on a horizontal frictionless surface with a speed of 2.0 m/sw. d. zgmcz,zgpl(4 u7?

  05.03: What is the centripetal acceleration of an objectb85y ;7 10fuw 4p;ivw8olegdidja *i n (mass = 50 g) on the end of an 80-cm string rotating at a constant rate of 4 times wiad0j deyn*w8u 5p8 fi ol1i4;7;bvg a second?

  09.24: A point mass moves along a holsch ; qf u(am5)vg(*q 3xh,rwrizontal circular path of radius 0.8m with a constant kinetic energy of 128J. What is 3sf*rh wqu;5xqam( ,(l) hvc gthe 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 . l3ci sg+nh8q ,coyk-in a horizontal circle at a constant speed of 6.0 m/s. See figure to the right. The work done on the ball during each revolutioo-ns,igyl3c +k8qh. cn is:

  99.22: A child whirls a ball at the end of a rope, in a uniform circulq+orebh,)n 9(l0b )s8o6u v1ixv abgwar motion. Which of the following souv bbrxq,l 0s)8noa+6 bw(h9 e)igv1tatements is NOT true?

  00.19: An astronaut in an orbiting space craft att hxp ;qe0o:a/eaches 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 ;e0eaoq : ph/xF. 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 lengthdf0q, 5mnhe fs9sj 9q: 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 string 90dehf s,qfsnj95:mq when the mass swings through the bottom ofthe arc?

  94.15: A car is traveling on a road in hilly terrain, see figure to thxo6gpgvg alw+1 )so+*8vsn-7s4 sgi ee right. Assume the car has speed v and the tops and botto 4ono7p6iegwss+1vlg8g -v*g x)as +s ms 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 moc+ sq ie;vmu d43b6ej6i/b.vi ves over 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 cb s3q6/;ie6me 4i v.j ud+cbivhoices best represents the magnitude of the upward force exerted by the road on the car?

  97.13: A small sphere is movsb3tm1)h(k z6v9sea j/mg9 v fing in a vertical circle at constant speed. The magnitude of the eb3vz v6m9 mgj1)k sh(t9saf/net force on the sphere

  11.47: A simple pendulum of lengvfz*f vfs0b 3xh5 b:r)th Lhasa point mass M released from rest from the horizontal position shown. In the absence of air resish3fs0 )* vxbfv:bz5 frtance 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 among these forces when the mass swings at the bottom of the arc (point P)?

  16.32: A mass connected to fgr.e3nzm9ja/e b2 -sa 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 gj-.3/ze92 ms a fengrbravitational 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 j,6iv88xf0etwlft f7s9vf;t rubber stopper moving at a constant speed in a horizontal circle. If the same force is applied, but the radius is made smaller, what hv96f0i 7 sl xt8tf 8ewfj,;tfvappens to the speed v, and the frequency f, of the stopper?

  05.28: A mass, M, is at rest o:ude 1uxy3(s x/ +9lp v,ozdeuc8 h;iqn 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 thzoe; cx/sqv u 9dxh,p(183yluu+ id :eis 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 speed of 3.24 m/s in a vjqnlx3..xb.p *ebo.qerticall npj.xx o. *qbe3.q.bly-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 circle?

  14.23:Two small identical coins (labeled X andY) are at reston a horgyx8yqt3e8zxe +m 0vex..oywg 00 e4hizontal disk rot eg8zxg0e40 weq+yxy3ve 0ho x8 y..mtating at a 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 cup/uuc-gs 6 m,onnected 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 stri gus-u/pm6c,u ng 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 in thembw5 vm2rca2kr:v) c. figure. The string to which the mass is attached has a length of L = 3.00 m and forms an mmcwab:kv rr.)25v 2c 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 fr5ge/ clap7r q u36hm)uxi 93dtom a horizontal disk’s ca36 75 pgum9 uh)xi q3edrt/lcenter. 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 distanonsibc- 3m w5a+ ,l+jvvfm8c, ce R =1.75 m from the fixed center of a disk as shownim vv, f3b,wcaj5co l8++-s nm in the figure. The disk 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 cir n77in+: jmnql y)nz3ve :s9urcle, starting at the top, with initial speed 17.0n 7:jm z3:+sy)in elnr 9nv7uq 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 circle, starting at the top, with initial speed tgs w+lr ,3 dce+/kqn, 17.0 m/s. The object’s speed increases uniformly until it has moved counterclockwi, q+rewck3s gl/t+ d,nse 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 a6.zi 3dx;h mhb y)z*o7uiue9jt 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 hz*.dyhu7u bi)jo63x emz ;9i 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.