Question 1

If an irregularly shaped object (such as a wrench) is dropped from rest in a classroom and feels no air resistance, it will

Accepted Answer

A)  accelerate but will not spin. 
B)  accelerate and turn until its center of gravity reaches its lowest point. 
C)  accelerate and turn about its center of gravity with uniform angular speed. 
D)  accelerate and turn about its center of gravity with uniform angular acceleration. 
E)  accelerate and spin until its center of gravity reaches its highest point. 
A)  accelerate but will not spin. 
B)  accelerate and turn until its center of gravity reaches its lowest point. 
C)  accelerate and turn about its center of gravity with uniform angular speed. 
D)  accelerate and turn about its center of gravity with uniform angular acceleration. 
E)  accelerate and spin until its center of gravity reaches its highest point.

Question 2

In the figure, a 60-cm length of uniform wire, of 60 g mass and negligible thickness, is bent into a right triangle. The x and y coordinates of the center of mass, in cm, are closest to

Accepted Answer

A)  (8, 3). 
B)  (8, 5). 
C)  (9, 4). 
D)  (10, 3). 
E)  (10, 5). 
A)  (8, 3). 
B)  (8, 5). 
C)  (9, 4). 
D)  (10, 3). 
E)  (10, 5).

Question 3

A turbine blade rotates with angular velocity ω(t) = 2.00 rad/s- 2.1.00 rad/s3   . What is the angular acceleration of the blade at

Accepted Answer

A)  -38.2 rad/   
B)  -19.1 rad/   
C)  -86.0 rad/   
D)  -36.2 rad/   
E)  -172 rad/   
A)  -38.2 rad/   
B)  -19.1 rad/   
C)  -86.0 rad/   
D)  -36.2 rad/   
E)  -172 rad/

Question 4

When you ride a bicycle, in what direction is the angular velocity of the wheels?

Accepted Answer

A)  to your left 
B)  to your right 
C)  forwards 
D)  backwards 
E)  up 
A)  to your left 
B)  to your right 
C)  forwards 
D)  backwards 
E)  up

Question 5

When a rigid body rotates about a fixed axis, all the points in the body have the same

Accepted Answer

A)  tangential speed. 
B)  angular acceleration. 
C)  tangential acceleration. 
D)  linear displacement. 
E)  centripetal acceleration. 
A)  tangential speed. 
B)  angular acceleration. 
C)  tangential acceleration. 
D)  linear displacement. 
E)  centripetal acceleration.

Question 6

In the figure, a uniform ladder 12 meters long rests against a vertical frictionless wall. The ladder weighs 400 N and makes an angle θ of 79° with the floor. A man weighing 790 N climbs slowly up the ladder When he has climbed to a point that is 7.8 m from the base of the ladder, the ladder starts to slip. What is the coefficient of static friction between the floor and the ladder?

Accepted Answer

The answer of In the figure, a uniform ladder 12...

Question 7

A 3.45-kg centrifuge takes 100 s to spin up from rest to its final angular speed with constant angular acceleration. A point located 8.00 cm from the axis of rotation of the centrifuge moves with a speed of 150 m/s when the centrifuge is at full speed.
(a) What is the angular acceleration (in rad/s2) of the centrifuge as it spins up?
(b) How many revolutions does the centrifuge make as it goes from rest to its final angular speed?

Accepted Answer

(a) 18.8 r

Question 8

A 30.0-kg child sits on one end of a long uniform beam having a mass of 20.0 kg, and a 40.0-kg child sits on the other end. The beam balances when a fulcrum is placed below the beam a distance 1.10 m from the 30.0-kg child. How long is the beam?

Accepted Answer

A)  2.12 m 
B)  1.98 m 
C)  1.93 m 
D)  2.07 m 
E)  2.20 m 
A)  2.12 m 
B)  1.98 m 
C)  1.93 m 
D)  2.07 m 
E)  2.20 m

Question 9

In the figure, the rotor of a gyroscope is a uniform disk that has a radius of 13.8 cm and a moment of inertia about its axis of 4.0 × 10-3 kg ∙ m2. The length of the rotor shaft is 6.9 cm. The ball pivot at P is frictionless. At a given instant, the rotor shaft is horizontal and the rotor is rotating with an angular velocity of 90 rad/s about its axis OP, as shown. The rotor is viewed from point Q on the axis. The precessional linear velocity of point O, including the direction seen from point Q, is closest to

Accepted Answer

A)  0.054 m/s, leftward 
B)  0.054 m/s, upward 
C)  0.054 m/s, rightward 
D)  0.11 m/s, downward 
E)  0.11 m/s, rightward 
A)  0.054 m/s, leftward 
B)  0.054 m/s, upward 
C)  0.054 m/s, rightward 
D)  0.11 m/s, downward 
E)  0.11 m/s, rightward

Question 10

Two identical ladders are 3.0 m long and weigh 600 N each. They are connected by a hinge at the top and are held together by a horizontal rope, 1.0 m above the smooth floor forming a symmetric "A" arrangement. The angle between the ladders is 60° and both ladders have their center of gravity at their midpoint. What is the tension in the rope?

Accepted Answer

A)  240 N 
B)  300 N 
C)  220 N 
D)  260 N 
E)  280 N 
A)  240 N 
B)  300 N 
C)  220 N 
D)  260 N 
E)  280 N

Question 11

In the figure, point P is at rest when it is on the x-axis. The linear speed of point P when it reaches the y-axis is closest to

Accepted Answer

A)  0.18 m/s. 
B)  0.24 m/s. 
C)  0.35 m/s. 
D)  0.49 m/s. 
E)  0.71 m/s. 
A)  0.18 m/s. 
B)  0.24 m/s. 
C)  0.35 m/s. 
D)  0.49 m/s. 
E)  0.71 m/s.

Question 12

A uniform solid disk of radius 1.60 m and mass 2.30 kg rolls without slipping to the bottom of an inclined plane. If the angular velocity of the disk is   at the bottom, what is the height of the inclined plane?

Accepted Answer

A)  5.61 m 
B)  4.21 m 
C)  4.94 m 
D)  6.73 m 
A)  5.61 m 
B)  4.21 m 
C)  4.94 m 
D)  6.73 m

Question 13

Consider a uniform solid sphere of radius R and mass M rolling without slipping. Which form of its kinetic energy is larger, translational or rotational?

Accepted Answer

A)  Its translational kinetic energy is larger than its rotational kinetic energy. 
B)  Its rotational kinetic energy is larger than its translational kinetic energy. 
C)  Both forms of energy are equal. 
D)  You need to know the speed of the sphere to tell. 
A)  Its translational kinetic energy is larger than its rotational kinetic energy. 
B)  Its rotational kinetic energy is larger than its translational kinetic energy. 
C)  Both forms of energy are equal. 
D)  You need to know the speed of the sphere to tell.

Question 14

Three solid, uniform, cylindrical flywheels, each of mass 65.0 kg and radius 1.47 m rotate independently around a common axis. Two of the flywheels rotate in one direction at   the other rotates in the opposite direction at 3.42 rad/s. Calculate the magnitude of the net angular momentum of the system.

Accepted Answer

A)  298 kg ∙ m2/s 
B)  778 kg ∙ m2/s 
C)  257 kg ∙ m2/s 
D)  222 kg ∙ m2/s 
A)  298 kg ∙ m2/s 
B)  778 kg ∙ m2/s 
C)  257 kg ∙ m2/s 
D)  222 kg ∙ m2/s

Question 15

A lawn roller in the form of a uniform solid cylinder is being pulled horizontally by a horizontal force B applied to an axle through the center of the roller, as shown in the figure. The roller has radius 0.65 meters and mass 51 kg and rolls without slipping. What magnitude of the force B is required to give the center of mass of the roller an acceleration of   ?

Accepted Answer

The answer of A lawn roller in the form of...

Question 16

A dump truck has a large cubical concrete block in its bed. The coefficients of friction between this block and the floor of the bed are µk = 0.450 and µs = 0.650. As the bed is slowly tilted above the horizontal, will the brick first begin to slide or will it first tip over?

Accepted Answer

A)  It will first tip over. 
B)  It will first begin to slide. 
C)  It will tip over just as it begins to slide. 
D)  It is impossible to answer without knowing the mass of the block. 
E)  It is impossible to answer without knowing the dimensions of the block. 
A)  It will first tip over. 
B)  It will first begin to slide. 
C)  It will tip over just as it begins to slide. 
D)  It is impossible to answer without knowing the mass of the block. 
E)  It is impossible to answer without knowing the dimensions of the block.

Question 17

A machinist turns the power on to a grinding wheel, which is at rest at time t = 0.00 s. The wheel accelerates uniformly for 10 s and reaches the operating angular velocity of   The wheel is run at that angular velocity for 37 s and then power is shut off. The wheel decelerates uniformly at   until the wheel stops. In this situation, the time interval of angular deceleration (slowing down) is closest to:

Accepted Answer

A)  17 s 
B)  15 s 
C)  19 s 
D)  21 s 
E)  23 s 
A)  17 s 
B)  15 s 
C)  19 s 
D)  21 s 
E)  23 s

Question 18

If two vectors point in opposite directions, their cross product must be zero.

Accepted Answer

A)  True 
B)  False 
A)  True 
B)  False

Question 19

A 20.0-kg uniform plank is supported by the floor at one end and by a vertical rope at the other as shown in the figure. A 50.0-kg mass person stands on the plank a distance three-fourths of the length plank from the end on the floor.   (a) What is the tension in the rope?
(b) What is the magnitude of the force that the floor exerts on the plank?

Accepted Answer

The answer of A 20.0-kg uniform plank is supported by...

Question 20

If two vectors are perpendicular to each other, their cross product must be zero.

Accepted Answer

A)  True 
B)  False 
A)  True 
B)  False

Exam 12: Rotation of a Rigid Body

If an irregularly shaped object (such as a wrench) is dropped from rest in a classroom and feels no air resistance, it will

In the figure, a 60-cm length of uniform wire, of 60 g mass and negligible thickness, is bent into a right triangle. The x and y coordinates of the center of mass, in cm, are closest to

A turbine blade rotates with angular velocity ω(t) = 2.00 rad/s- 2.1.00 rad/s3 . What is the angular acceleration of the blade at

When you ride a bicycle, in what direction is the angular velocity of the wheels?

When a rigid body rotates about a fixed axis, all the points in the body have the same

A 30.0-kg child sits on one end of a long uniform beam having a mass of 20.0 kg, and a 40.0-kg child sits on the other end. The beam balances when a fulcrum is placed below the beam a distance 1.10 m from the 30.0-kg child. How long is the beam?

In the figure, point P is at rest when it is on the x-axis. The linear speed of point P when it reaches the y-axis is closest to

A uniform solid disk of radius 1.60 m and mass 2.30 kg rolls without slipping to the bottom of an inclined plane. If the angular velocity of the disk is at the bottom, what is the height of the inclined plane?

Consider a uniform solid sphere of radius R and mass M rolling without slipping. Which form of its kinetic energy is larger, translational or rotational?

A dump truck has a large cubical concrete block in its bed. The coefficients of friction between this block and the floor of the bed are µk = 0.450 and µs = 0.650. As the bed is slowly tilted above the horizontal, will the brick first begin to slide or will it first tip over?

If two vectors point in opposite directions, their cross product must be zero.

If two vectors are perpendicular to each other, their cross product must be zero.

Concepts of Motion

Kinematics in One Dimension

Vectors and Coordinate Systems

Kinematics in Two Dimensions

Force and Motion

Dynamics I: Motion Along a Line

Newtons Third Law

Dynamics Ii: Motion in a Plane

Work and Kinetic Energy

Interactions and Potential Energy

Impulse and Momentum

Newtons Theory of Gravity

Fluids and Elasticity

Oscillations

Traveling Waves

Superposition

A Macroscopic Description of Matter

Work, Heat, and the First Law of Thermodynamics

The Micromacro Connection

Heat Engines and Refrigerators

Electric Charges and Forces

The Electric Field

Gausss Law

The Electric Potential

Potential and Field

Current and Resistance

Fundamentals of Circuits

The Magnetic Field

Electromagnetic Induction

Electromagnetic Fields and Waves

Ac Circuits

Wave Optics

Ray Optics

Optical Instruments

Relativity

The Foundations of Modern Physics

Quantization

Wave Functions and Uncertainty

One-Dimensional Quantum Mechanics

Atomic Physics

Nuclear Physics

Filters

A turbine blade rotates with angular velocity ω(t) = 2.00 rad/s- 2.1.00 rad/s³ . What is the angular acceleration of the blade at

A dump truck has a large cubical concrete block in its bed. The coefficients of friction between this block and the floor of the bed are µ_k = 0.450 and µ_s = 0.650. As the bed is slowly tilted above the horizontal, will the brick first begin to slide or will it first tip over?