Chapter 8 p – Flashcards

1) Horses with the greatest linear speed on a merry-go-round are located A) near the center. B) near the outside. C) anywhere, because they all move at the same speed.

2) Which horse moves faster in m/s on a merry-go-round? A) one near inner rail B) one near outer rail C) both move at the same speed in m/s.

3) If a turntable's rotational speed is doubled, then the linear speed of a pet hamster sitting on the edge of the record will A) double. B) halve. C) remain the same.

4) Your pet hamster sits on a record player that has constant angular speed. If the hamster moves to a point twice as far from the center, then its linear speed A) doubles. B) halves. C) remains the same.

5) When railroad tracks make a curve, the outer track is longer. This means a wheel that rides on the outer track needs to somehow A) roll slower than the wheel on the inner track. B) maintain the same speed as the wheel on the inner track. C) roll faster than the wheel on the inner track.

6) When a train makes a curve, a tapered wheel rim is able to A) cover different distances per revolution. B) maintain a fixed rotational speed. C) reduce differences in angular speeds.

7) Each rolling wheel of a railroad train is tapered. Compared with the wide part, the narrow part of the wheel has a tangential speed that is A) less. B) greater. C) the same for both.

8) The tapered shape of the wheel rims that ride on railroad tracks allows opposite wheels to A) in effect, vary their diameters. B) travel at different linear speeds for the same rotational speed. C) both of these

9) The circumference of a bicycle wheel is 2 meters. If it rotates at 1 revolution per second then its linear speed is A) 1 m/s. B) 2 m/s. C) 3 m/s. D) 3.14 m/s. E) 6.28 m/s.

10) Consider a string with several rocks tied along its length at equally spaced intervals. You whirl the string overhead so that the rocks follow circular paths. Compared with a rock at the end of the string, a rock at the middle moves A) half as fast. B) twice as fast. C) at the same linear speed.

11) The net force exerted on a car traveling in a circular path at constant speed is A) directed forward, in the direction of travel. B) directed toward the center of the curve. C) zero because the car is not accelerating.

12) If you're on a Ferris wheel at a carnival, seated 10 m from the Ferris wheel's axis that makes a complete rotation each minute, your linear speed is A) 10 m/min. B) 31.4 m/min. C) 62.8 m/min. D) 100 m/min.

13) The rotational inertia of your leg is greater when your leg is A) straight. B) bent. C) same either way

14) You can swing your legs to and fro more frequently when your legs are A) straight. B) bent. C) same either way

15) An industrial flywheel has a greater rotational inertia when most of its mass is A) nearer the rim. B) nearer the axis. C) uniformly spread out as in a disk.

16) The rotational inertia of a pencil is greatest about an axis A) along its length, where the lead is. B) about its midpoint, like a propeller. C) about its end, like a pendulum.

17) Which of these animals has a quicker stride? A) giraffe B) horse C) cat D) mouse

18) A tightrope walker more easily balances on a tight wire if her pole A) is held high. B) droops. C) is short but heavy.

19) Consider two flywheels of the same size and shape, but one with twice the mass. Rotational inertia of the more massive one is A) two times greater. B) four times greater. C) half.

20) A flywheel's diameter is twice that of another of the same shape and mass. Rotational inertia of the larger flywheel is A) two times greater. B) four times greater. C) the same as the other's.

21) A coin and a ring roll down an incline at the same time. The one to first reach the bottom is the A) ring. B) coin. C) both reach the bottom at the same time

22) A ring and a disk both at rest roll down a hill together. Which rolls slower? A) ring B) disk C) both roll at the same speed

23) A ring, a disk, and a solid sphere begin rolling down a hill together. Which reaches the bottom first? A) ring B) disk C) sphere D) all reach the bottom at the same time

24) A vertically-held sledge hammer is easier to balance when the heavier end is A) on your hand. B) at the top, away from your hand. C) same either way

25) Stand a meterstick on its end and let it rotate to the floor. If you attach a heavy glob of clay to its upper end and repeat, the time to fall will be A) shorter. B) longer. C) the same.

26) A vertically-held sledge hammer is easier to balance when the heavier end is A) on your hand. B) at the top, away from your hand. C) the same either way

27) Stand a broom upright on the end of its pole and let it topple to the floor. Repeat, but with the bristles end on the floor. The faster fall will be the broom standing on its A) pole-end. B) bristles-end. C) the same either way

28) Stand a broom upright on the end of its pole and let it topple to the floor. Repeat, but with the bristles end on the floor. The faster fall will be the broom standing on its A) pole-end. B) bristles-end. C) the same either way.

29) Which jar will roll down an incline in the shortest time, an empty one or one filled with peanut butter? A) the empty jar B) both reach the bottom at the same time C) the filled jar

30) Which tin can will roll down an incline in the shortest time, one filled with water or one filled with ice? (Hint: water 'slides' inside the can.) A) with water B) with ice C) both the same

31) Compared with a force, a torque involves A) rotation. B) leverage. C) distance from an axis of rotation. D) all the above

32) A torque acting on an object tends to produce A) equilibrium. B) rotation. C) linear motion. D) velocity.

33) If Alex wishes to rotate his skateboard, then he must apply a A) torque. B) rotational maneuver. C) pause before bearing down on the board.

34) A ball that gains speed as it rolls down a hill experiences a A) net torque. B) net force. C) both of these D) neither of these

35) If you place a pipe over the end of a wrench when trying to rotate a stubborn bolt, effectively making the wrench handle twice as long, you'll multiply the torque by A) two. B) four. C) eight.

36) For a system in mechanical equilibrium, the resultant A) force must be zero. B) torque must be zero. C) both of these D) none of these

37) A ball gains speed while rolling down a hill due mainly to A) its rotational inertia. B) its angular acceleration. C) a balanced torque. D) an unbalanced torque.

38) To rotate a stubborn screw, it is best to use a screwdriver that has a A) wide handle. B) long handle. C) smooth handle. D) none of the above

39) Two people are balanced on a seesaw. If one person leans inward toward the center of the seesaw, that person's end of the seesaw tends to A) rise. B) fall. C) stay at the same level. D) need more information

40) On a balanced seesaw, a boy three times as heavy as his partner sits A) less than 1/3 the distance from the fulcrum. B) 1/3 the distance from the fulcrum. C) more than 1/3 the distance from the fulcrum.

41) A solitary boy cannot balance on a seesaw with its fulcrum at its midpoint. If the fulcrum is moved to one-quarter the distance from the boy, balance is achieved when the weight of the boy is A) less than the weight of the seesaw. B) equal to the weight of the seesaw. C) more than the weight of the seesaw. D) need more information

42) A boy plays solitary seesaw by placing the seesaw's fulcrum one-eighth the distance from where he sits at one end. Which weighs more? A) the boy B) the seesaw C) they have equal weights D) need more information

43) Toss a baseball bat into the air and it wobbles about its A) geometrical center. B) center of mass. C) heavier end.

44) The long, heavy tail of a spider monkey enables the monkey to easily vary its A) weight. B) momentum. C) inertia. D) center of gravity. E) none of the above

45) The center of mass of a human body is located at a point that A) is fixed, but different for different people. B) is always directly behind the belly button. C) changes as a person bends over. D) none of the above