Question 1

A 30.0 cm wrench is used to generate a torque at a bolt.A force of 40 N is applied perpendicularly at the end of the wrench.The torque generated at the bolt is

Accepted Answer

A)  5.0 N.m. 
B)  7.0 N.m. 
C)  9.0 N.m. 
D)  12 N.m. 
E)  20 N.m. 
A)  5.0 N.m. 
B)  7.0 N.m. 
C)  9.0 N.m. 
D)  12 N.m. 
E)  20 N.m. D

Question 2

A torque of 20.0 N.m is applied to a bolt.The bolt rotates through an angle of 180 degrees.The work done in turning the bolt is

Accepted Answer

A)  72.5 J. 
B)  51.9 J. 
C)  62.8 J. 
D)  49.9 J. 
E)  58.4 J. 
A)  72.5 J. 
B)  51.9 J. 
C)  62.8 J. 
D)  49.9 J. 
E)  58.4 J. C

Question 3

An 8.0 kg object has a moment of inertia of 1.00 kg m2.What torque is needed to give the object an angular acceleration of 1.5 rad/s2?

Accepted Answer

A)  3.0 N.m 
B)  2.5 N.m 
C)  2.0 N.m 
D)  1.5 N.m 
E)  1.0 N.m 
A)  3.0 N.m 
B)  2.5 N.m 
C)  2.0 N.m 
D)  1.5 N.m 
E)  1.0 N.m D

Question 4

A mass m1 is connected by a light string that passes over a pulley of mass M to a mass m2 sliding on a frictionless horizontal surface as shown in the figure.There is no slippage between the string and the pulley.The pulley has a radius of 25.0 cm and a moment of inertia of 1/2 MR2.If m1 is 1.00 kg,m2 is 2.00 kg,and M is 4.00 kg,then what is the tension in the string attached to m1?

Accepted Answer

A)  6.83 N 
B)  7.03 N 
C)  7.84 N 
D)  8.02 N 
E)  8.33 N 
A)  6.83 N 
B)  7.03 N 
C)  7.84 N 
D)  8.02 N 
E)  8.33 N

Question 5

Chris and Jamie are carrying Wayne on a horizontal stretcher.The uniform stretcher is 2.00 m long and weighs 100 N.Wayne weighs 800 N.Wayne's center of gravity is 75.0 cm from Chris.Chris and Jamie are at the ends of the stretcher.The force that Jamie is exerting to support the stretcher,with Wayne on it,is

Accepted Answer

A)  250 N. 
B)  300 N. 
C)  350 N. 
D)  400 N. 
E)  550 N. 
A)  250 N. 
B)  300 N. 
C)  350 N. 
D)  400 N. 
E)  550 N.

Question 6

An 8.00 kg object has a moment of inertia of 1.50 kg m2.If a torque of 2.00 N.m is applied to the object,the angular acceleration is

Accepted Answer

A)  0.750 rad/s2. 
B)  1.00 rad/s2. 
C)  1.33 rad/s2. 
D)  2.01 rad/s2. 
E)  2.67 rad/s2. 
A)  0.750 rad/s2. 
B)  1.00 rad/s2. 
C)  1.33 rad/s2. 
D)  2.01 rad/s2. 
E)  2.67 rad/s2.

Question 7

A mass m1 is connected by a light string that passes over a pulley of mass M to a mass m2 sliding on a frictionless incline as shown in the figure.There is no slippage between the string and the pulley.The pulley has a radius of 30.0 cm and a moment of inertia of MR2.If m1 is 4.00 kg,m2 is 4.00 kg,M is 4.00 kg,and the angle is 70.0 degrees,then what is the acceleration of m1?

Accepted Answer

A)  3.10 m/s2 
B)  2.89 m/s2 
C)  2.43 m/s2 
D)  2.15 m/s2 
E)  1.49 m/s2 
A)  3.10 m/s2 
B)  2.89 m/s2 
C)  2.43 m/s2 
D)  2.15 m/s2 
E)  1.49 m/s2

Question 8

A 6.00 kg mass is located at (1.0 m,-2.00 m,3.00 m),a 5.00 kg mass is located at (1.0 m,3.00 m,-2.00 m),and a 4.00 kg mass is located at (-1.0 m,-2.00 m,2.00 m).The center of gravity of the system of masses is

Accepted Answer

A)  (5/15m,-1/15m,17/15m). 
B)  (5/15m,-17/15m,5/15m). 
C)  (12/15m,-5/15m,16/15m). 
D)  (7/15m,-5/15m,16/15m). 
E)  (16/15m,-1/15m,17/15m). 
A)  (5/15m,-1/15m,17/15m). 
B)  (5/15m,-17/15m,5/15m). 
C)  (12/15m,-5/15m,16/15m). 
D)  (7/15m,-5/15m,16/15m). 
E)  (16/15m,-1/15m,17/15m).

Question 9

A 30.0 cm wrench is used to generate a torque at a bolt.A force of 50.0 N is applied at the end of the wrench at an angle of 70.0 degrees.The torque generated at the bolt is

Accepted Answer

A)  10.4 N.m. 
B)  14.1 N.m. 
C)  19.7 N.m. 
D)  21.5 N.m. 
E)  26.2 N.m. 
A)  10.4 N.m. 
B)  14.1 N.m. 
C)  19.7 N.m. 
D)  21.5 N.m. 
E)  26.2 N.m.

Question 10

A 4.00 kg hollow sphere (I = 2/3 MR2)is spinning with an angular velocity of 10.0 rad/s.The diameter of the sphere is 20.0 cm.The angular kinetic energy of the spinning sphere is

Accepted Answer

A)  1.75 J. 
B)  1.50 J. 
C)  1.33 J. 
D)  0.90 J. 
E)  0.75 J. 
A)  1.75 J. 
B)  1.50 J. 
C)  1.33 J. 
D)  0.90 J. 
E)  0.75 J.

Question 11

A 2.00 m long horizontal uniform beam of mass 20.0 kg is supported by a wire as shown in the figure.The wire makes an angle of 20.0 degrees with the beam.Attached to the beam 1.40 m from the wall is a ball with a mass of 40 kg.What is the tension in the string?

Accepted Answer

A)  1,000 N 
B)  1,090 N 
C)  2,100 N 
D)  2,250 N 
E)  2,680 N 
A)  1,000 N 
B)  1,090 N 
C)  2,100 N 
D)  2,250 N 
E)  2,680 N

Question 12

A thin rod is pivoted around its end,and an identical rod around its center.If they are to have the same rotational kinetic energy,then $\omega_{end}$/$\omega_{center}$ =

Accepted Answer

A)  2 
B)  1 
C)  1/2 
D)  1/4 
E)  4 
A)  2 
B)  1 
C)  1/2 
D)  1/4 
E)  4

Question 13

A propeller is spun up from rest to 1500 rpm under the influence of a constant torque in 15.0s.If the work done by the engine in giving the propeller its final angular velocity is 25kJ,what is the torque supplied by the engine?

Accepted Answer

A)  21Nm 
B)  11 Nm 
C)  42 Nm 
D)  21 Nm 
E)  130 Nm 
A)  21Nm 
B)  11 Nm 
C)  42 Nm 
D)  21 Nm 
E)  130 Nm

Question 14

Chris and Jamie are carrying Wayne on a horizontal stretcher.The uniform stretcher is 2.00 m long and weighs 100 N.Wayne weighs 800 N.Wayne's center of gravity is 75.0 cm from Chris.Chris and Jamie are at the ends of the stretcher.The force that Chris is exerting to support the stretcher,with Wayne on it,is

Accepted Answer

A)  250 N. 
B)  350 N. 
C)  400 N. 
D)  550 N. 
E)  650 N. 
A)  250 N. 
B)  350 N. 
C)  400 N. 
D)  550 N. 
E)  650 N.

Question 15

A 10 kg sphere with a 25.0 cm radius has a moment of inertia of 2/5 MR2.If a torque of 2.0 N.m is applied to the object,the angular acceleration is

Accepted Answer

A)  1.0 rad/s2. 
B)  2.0 rad/s2. 
C)  4.0 rad/s2. 
D)  6.0 rad/s2. 
E)  8.0 rad/s2. 
A)  1.0 rad/s2. 
B)  2.0 rad/s2. 
C)  4.0 rad/s2. 
D)  6.0 rad/s2. 
E)  8.0 rad/s2.

Question 16

A 1.500 m long uniform beam of mass 30.00 kg is supported by a wire as shown in the figure.The beam makes an angle of 10.00 degrees with the horizontal and the wire makes and angle of 30.00 degrees with the beam.A 50.00 kg mass,m,is attached to the end of the beam.What are the vertical and horizontal components of the force of the wall on the beam at the hinge?

Accepted Answer

A)  H = 1,458 N,V = 454.0 N 
B)  H = 1,300 N,V = 403.4 N 
C)  H = 1,179 N,V = 354.9 N 
D)  H = 979 N,V = 324.5 N 
E)  H = 750 N,V = 297.3 N 
A)  H = 1,458 N,V = 454.0 N 
B)  H = 1,300 N,V = 403.4 N 
C)  H = 1,179 N,V = 354.9 N 
D)  H = 979 N,V = 324.5 N 
E)  H = 750 N,V = 297.3 N

Question 17

A 0.50kg disk spins at 250rpm.A torque of 12.5Nm is applied for 0.150s to bring it to rest.What is the disk's radius?

Accepted Answer

A)  0.54m 
B)  0.38m 
C)  0.29m 
D)  0.14m 
A)  0.54m 
B)  0.38m 
C)  0.29m 
D)  0.14m

Question 18

A 5.00 kg mass is located at (2.00 m,0.00 m,3.00 m)and a 2.00 kg mass is located at (0.00 m,4.00 m,-2.00 m).The center of gravity of the system of masses is

Accepted Answer

A)  (10/7m,8/7m,11/7m). 
B)  (11/7m,7/7m,8/7m). 
C)  (7/7m,10/7m,11/7m). 
D)  (10/7m,7/7m,8/7m). 
E)  (8/7m,7/7m,10/7m). 
A)  (10/7m,8/7m,11/7m). 
B)  (11/7m,7/7m,8/7m). 
C)  (7/7m,10/7m,11/7m). 
D)  (10/7m,7/7m,8/7m). 
E)  (8/7m,7/7m,10/7m).

Question 19

A 25.0kg propeller may be considered a 4.5m-long rod spun about its center.What final angular velocity does the propeller have if a torque of 1100Nm is applied for 1.2s?

Accepted Answer

A)  31 rad/s 
B)  26 rad/s 
C)  7.8 rad/s 
D)  2.6 rad/s 
A)  31 rad/s 
B)  26 rad/s 
C)  7.8 rad/s 
D)  2.6 rad/s

Question 20

An auto mechanic is attempting to loosen a bolt in an engine using a large wrench,but to no avail.If she applies a force of 510N perpendicular to the wrench she is using,applied at 0.75m from the axis of rotation of the bolt,what is the value of the friction force applied to the outer surface of the bolt's threads? The threaded portion of the bolt has diameter 1.2cm.

Accepted Answer

A)  3.2 kN 
B)  510N 
C)  32kN 
D)  1.6kN 
E)  16kN 
A)  3.2 kN 
B)  510N 
C)  32kN 
D)  1.6kN 
E)  16kN

Exam 8: Torque and Angular Momentum

A 30.0 cm wrench is used to generate a torque at a bolt.A force of 40 N is applied perpendicularly at the end of the wrench.The torque generated at the bolt is

A torque of 20.0 N.m is applied to a bolt.The bolt rotates through an angle of 180 degrees.The work done in turning the bolt is

An 8.0 kg object has a moment of inertia of 1.00 kg m2.What torque is needed to give the object an angular acceleration of 1.5 rad/s2?

An 8.00 kg object has a moment of inertia of 1.50 kg m2.If a torque of 2.00 N.m is applied to the object,the angular acceleration is

A 6.00 kg mass is located at (1.0 m,-2.00 m,3.00 m),a 5.00 kg mass is located at (1.0 m,3.00 m,-2.00 m),and a 4.00 kg mass is located at (-1.0 m,-2.00 m,2.00 m).The center of gravity of the system of masses is

A 30.0 cm wrench is used to generate a torque at a bolt.A force of 50.0 N is applied at the end of the wrench at an angle of 70.0 degrees.The torque generated at the bolt is

A 4.00 kg hollow sphere (I = 2/3 MR2)is spinning with an angular velocity of 10.0 rad/s.The diameter of the sphere is 20.0 cm.The angular kinetic energy of the spinning sphere is

A 2.00 m long horizontal uniform beam of mass 20.0 kg is supported by a wire as shown in the figure.The wire makes an angle of 20.0 degrees with the beam.Attached to the beam 1.40 m from the wall is a ball with a mass of 40 kg.What is the tension in the string?

A thin rod is pivoted around its end,and an identical rod around its center.If they are to have the same rotational kinetic energy,then ωend\omega_{end}ωend​ / ωcenter\omega_{center}ωcenter​ =

A propeller is spun up from rest to 1500 rpm under the influence of a constant torque in 15.0s.If the work done by the engine in giving the propeller its final angular velocity is 25kJ,what is the torque supplied by the engine?

A 10 kg sphere with a 25.0 cm radius has a moment of inertia of 2/5 MR2.If a torque of 2.0 N.m is applied to the object,the angular acceleration is

A 0.50kg disk spins at 250rpm.A torque of 12.5Nm is applied for 0.150s to bring it to rest.What is the disk's radius?

A 5.00 kg mass is located at (2.00 m,0.00 m,3.00 m)and a 2.00 kg mass is located at (0.00 m,4.00 m,-2.00 m).The center of gravity of the system of masses is

A 25.0kg propeller may be considered a 4.5m-long rod spun about its center.What final angular velocity does the propeller have if a torque of 1100Nm is applied for 1.2s?

Introduction

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Acceleration and Newtons Second Law of Motion

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Conservation of Energy

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An 8.0 kg object has a moment of inertia of 1.00 kg m².What torque is needed to give the object an angular acceleration of 1.5 rad/s²?

An 8.00 kg object has a moment of inertia of 1.50 kg m².If a torque of 2.00 N.m is applied to the object,the angular acceleration is

A 4.00 kg hollow sphere (I = 2/3 MR²)is spinning with an angular velocity of 10.0 rad/s.The diameter of the sphere is 20.0 cm.The angular kinetic energy of the spinning sphere is

A thin rod is pivoted around its end,and an identical rod around its center.If they are to have the same rotational kinetic energy,then $\omega_{end}$ / $\omega_{center}$ =

A 10 kg sphere with a 25.0 cm radius has a moment of inertia of 2/5 MR².If a torque of 2.0 N.m is applied to the object,the angular acceleration is