Chapter 7 Rotational Motion 7.1 Angular Quantities ...

1 I01. Convert the following angle measurements to ) ) ) The Empire State Building has a total height of m (including the lightning rod). From one observation pointon a street in New York, it subtends an angle of How far from the building is this observation point?03. A laser beam, shining from the earth's surface, is directed at the moon whose distance from the earth on this day is370,000 km. If the beam diverges at an angle of only x 10-5rad, what diameter circle will it make on themoon?04. A Compact Disc (CD) has a diameter of cm, rotates at a constant 207 rpm, and has a total playing time ) What is the Angular velocity of the CD?

2 B.) What is the linear speed of a point on the edge of the disc?c.) What is the Angular displacement of the CD during its total play time?d.) What is the distance traveled by a point on the edge of the CD?e.) What is the distance traveled by a point cm from the center of the CD?f.) What is the Angular acceleration of the CD during its total play time?g.) What is the tangential acceleration of a point on the edge of the CD?h.) What is the centripetal acceleration of a point on the edge of the CD?05. An antique grinding wheel rotating at rpm is brought to rest in s. What is its Angular acceleration?

3 II06. A centrifuge is rotated from rest to 18,000 rpm in 4 minutes and 45 seconds. What is the average angularacceleration of the centrifuge during this time?07. A bicycle with tires of diameter cm travels km. How many revolutions do the wheels make?08. Calculate the Angular velocity of the earth ) in its orbit around the sunb.) about its axis09. What is the linear speed of a point _____ due to the earth's rotation about its axis. (SeeHomework #26in" Chapter 4-Circular Motion & Gravitation" for the table of "Planetary Data")a.) on the equatorb.) at a latitude of A phonograph record with a diameter of cm reaches its rated speed of 33 rpm in ) What is the tangential component of the linear acceleration of a point on the edge of the record?

4 B.) What is the centripetal component of the linear acceleration of a point on the edge of the record s after itstarts rotating? Chapter 7 Rotational Angular QuantitiesHomework # 51 ) radb.) radc.) ) ) m/sc.) x 104radd.) 5775 me.) 3850 mf.) 0 rad/s2g.) 0 m/s2h.) ) x 10-7rad/sb.) x 10-5 ) 464 m/sb.) 232 ) m/s2b.) m/s2I01. A phonograph turntable reaches its rated speed of 33 rpm in revolutions. What is its Angular acceleration?02. A centrifuge accelerates from rest to 12,000 rpm in 235 s. What was the centrifuge's Angular acceleration?II03. A truck engine slows down from 3700 rpm to 1800 rpm in s.

5 How many revolutions were made by theengine during this time?04. A car, with 26-inch ( )-diameter wheels, accelerates from rest to km/h ( mi/h) in 295 ) What is the Angular displacement of the wheels?b.) What is theAVERAGE Angular velocity of the wheels?c.) What is the Angular acceleration of the wheels?d.) How long did it take to reach this speed?05. A train that has wheels with a diameter of cm (36 inches used for 100 ton capacity cars) slows down km/h to km/h as the train approaches a town. The wheels of the train make revolutions in this ) What is the Angular acceleration of the wheels?

6 B.) How long does it take the train to make this reduction in speed?c.) How far does the train travel during this deceleration period?d.) Assuming the same rate of deceleration, how manyMORE revolutions will the wheels make before stopping?e.) Assuming the same rate of deceleration, how muchFARTHER will the train travel before stopping?06. A bicycle wheel (Wheel 1) with a diameter of cm is mounted such that its circular edge touches that of asecond bicycle wheel (Wheel 2) with a diameter of cm. Wheel 1 accelerates at a rate of rad/s2anddrives the second wheel through its contact with negligible ) How long will it take Wheel 1, starting from rest, to reach a rotation rate of rpm?

7 B.) What is the linear speed of a point on the edge of Wheel 1 when it rotates at rpm?c.) How far does a point on the edge of Wheel 1 travel in the time needed to reach a rotation rate of rpm?d.) What is the Angular acceleration of Wheel 2?e.) How long will it take Wheel 2, starting from rest, to reach a rotation rate of rpm?f.) What is the linear speed of a point on the edge of Wheel 2 when it rotates at rpm?g.) How far does a point on the edge of Wheel 2 travel in the time needed to reach a rotation rate of rpm?III07. A bicycle wheel accelerates from 165 rpm to 280 rpm in s. How far will the bicycle have traveledin this time?

8 Chapter 7 Rotational Uniformly Accelerated Rotational MotionHomework # 52 ) 894 radb.) ) rad/s2d.) ) rad/s2b.) sc.) 273 md.) reve.) ) sb.) m/sc.) md.) rad/s2e.) sf.) m/sg.) mI01. A person is riding a bike whose pedals rotate in a circle with a diameter of cm. What is themaximum torque exerted by the rider on the pedals assuming he puts all of his weight on the pedals?02. A woman opens an wide door for a man by applying a force of N to the edge of the ) Calculate the maximum torque applied to the ) Calculate the torque applied to the door if the force is applied at a to the face of the A 12 foot length of 2" x 12" lumber (white pine), weighing lbs, is sitting on the ground.

9 What minimumupward force is needed to lift the one end of the wood, assuming the other end does not slide, but rather acts asthe axis of rotation. Ignore any bending of the Assume the same piece of lumber as problem 03 above isagain sitting on the ground. This time there are two packagesof roofing shingles sitting on the wood. One package, that isunopened, weighs 80 lbs (w1) and is positioned feet fromthe left end of the board; while the other package, that is not afull package, weighs 55 lbs (w2) and is positioned feetfrom the right end of the board as shown in the diagram to theright.

10 What minimum upward force is needed to lift the rightend of the board? Ignore any bending of the What is the net torque applied to the wheel and axle assembly shown in thediagram to the right? Assume a frictional torque of . The axle has aradius of mm and the wheel has a radius of mm. All forces The wheel lug nuts of a 1988 Jeep Wrangler require tightening to a torque of 80 ). A mechanic uses a long wrench (shown in the diagram below).a.) What is the minimum force needed by a mechanic to tighten this nut to factoryspecifications?b.) What force is applied to each point on the six-sided nut with a diameter of mmwhen the bolt is tightened to factory specifications?