A uniform bridge span weighs 50.0 ´ 103 N and is 40.0 m long.An automobile weighing 15.0 ´ 103 N is parked with its center of gravity located 12.0 m from the right pier.What upward support force does the left pier provide?

A) 29.5 ´ 103 N B) 35.5 ´ 103 N C) 65.0 ´ 103 N D) 32.5 ´ 103 N A) 29.5 ´ 103 N B) 35.5 ´ 103 N C) 65.0 ´ 103 N D) 32.5 ´ 103 N

A ventilation fan with a moment of inertia of 0.034 kg*m2 has a net torque of 0.11 N*m applied to it.If it starts from rest,what kinetic energy will it have 8.0 s later?

A) 31 J B) 17 J C) 11 J D) 6.6 J A) 31 J B) 17 J C) 11 J D) 6.6 J

Exam 8: Rotational Equilibrium and Rotational Dynamics

A baseball pitcher loosens up his pitching arm.He tosses a 0.15-kg ball using only the rotation of his forearm,0.32 m in length,to accelerate the ball.What is the moment of inertia of the ball alone as it moves in a circular arc with a radius of 0.32 m?

(Multiple Choice)

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Question 21

Two hoops or rings (I = MR²)are centered,lying on a turntable.The smaller ring has radius = 0.050 m;the larger has radius = 0.10 m.Both have a mass of 3.0 kg.What is the total moment of inertia as the turntable spins? Ignore the mass of the turntable.

(Multiple Choice)

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Question 22

An initially installed flywheel can store 10⁶ J of kinetic energy when rotating at 300 rad/s.It is replaced by another flywheel of the same size but made of a lighter and stronger material.If its mass is half that of the original and it is now capable of achieving a rotational speed of 600 rad/s,what maximum energy can be stored?

(Multiple Choice)

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Question 23

A cylinder (I = MR²/2)is rolling along the ground at 7.0 m/s.It comes to a hill and starts going up.Assuming no losses to friction,how high does it get before it stops?

(Multiple Choice)

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Question 24

The torque caused by a force F applied at a distance r from the axis of rotation,is given by $The torque caused by a force F applied at a distance r from the axis of rotation,is given by ,where q is the angle between and .If the magnitudes r and F remain the same,what other angle q¢ will produce the same torque as was produced at angle q if q was less than 90 \degree ?$ ,where q is the angle between $The torque caused by a force F applied at a distance r from the axis of rotation,is given by ,where q is the angle between and .If the magnitudes r and F remain the same,what other angle q¢ will produce the same torque as was produced at angle q if q was less than 90 \degree ?$ and $The torque caused by a force F applied at a distance r from the axis of rotation,is given by ,where q is the angle between and .If the magnitudes r and F remain the same,what other angle q¢ will produce the same torque as was produced at angle q if q was less than 90 \degree ?$ .If the magnitudes r and F remain the same,what other angle q¢ will produce the same torque as was produced at angle q if q was less than 90 $\degree$ ?

(Multiple Choice)

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Question 25

A 100-N uniform ladder,8.0 m long,rests against a smooth vertical wall.The coefficient of static friction between ladder and floor is 0.40.What minimum angle can the ladder make with the floor before it slips?

(Multiple Choice)

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Question 26

The quantity "angular momentum" (in terms of the fundamental quantities of mass,length,and time)is equivalent to:

(Multiple Choice)

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Question 27

A vault is opened by applying a force of 300 N perpendicular to the plane of the door,0.80 m from the hinges.Find the torque due to this force about an axis through the hinges.

(Multiple Choice)

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Question 28

A 2.00-m by 4.00-m uniform sheet of plywood is in a coordinate system with the origin at its center,the x-axis along the longer dimension of the sheet is positive to the right and the y-axis along the shorter dimension is positive upwards.The section of the plywood in the 3rd quadrant is sawed off and the resulting piece is then glued squarely over the 4th quadrant portion of the plywood with glue of negligible weight.What are the x- and y-coordinates of the resulting center of gravity for this arrangement?

(Multiple Choice)

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Question 29

A meter stick is supported by a knife-edge at the 50-cm mark.Doug hangs masses of 0.40 and 0.60 kg from the 20-cm and 80-cm marks,respectively.Where should Doug hang a third mass of 0.30 kg to keep the stick balanced?

(Multiple Choice)

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Question 30

An ice skater spins at 2.5 rev/s when his arms are extended.He draws his arms in and spins at 6.0 rev/s.By what factor does his moment of inertia change in the process?

(Multiple Choice)

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Question 31

A uniform bridge span weighs 50.0 ´ 10³ N and is 40.0 m long.An automobile weighing 15.0 ´ 10³ N is parked with its center of gravity located 12.0 m from the right pier.What upward support force does the left pier provide?

(Multiple Choice)

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Question 32

An astronaut is on a 100-m lifeline outside a spaceship,circling the ship with an angular speed of 0.100 rad/s.How far inward can she be pulled before the centripetal acceleration reaches 5g = 49 m/s²?

(Multiple Choice)

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Question 33

A rod of length L is pivoted about its left end and has a force F applied perpendicular to the other end.The force F is now removed and another force F' is applied at the midpoint of the rod.If F' is at an angle of 30 $\degree$ with respect to the rod,what is its magnitude if the resulting torque is the same as when F was applied?

(Multiple Choice)

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Question 34

A solid sphere of mass 4.0 kg and radius 0.12 m is at rest at the top of a ramp inclined 15 $\degree$ .It rolls to the bottom without slipping.The upper end of the ramp is 1.2 m higher than the lower end.Find the sphere's total kinetic energy when it reaches the bottom.

(Multiple Choice)

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Question 35

Two equal magnitude forces are in opposite directions and their lines of action are separated by distance d.These two forces are applied to a solid disk,which is mounted on a frictionless axle.If d is half the radius r of the disk,which of the following positions for the forces would give the most torque.

(Multiple Choice)

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Question 36

A uniform beam of length 3.00 m and weight 100 N is mounted on an axle at one end perpendicular to the length of the beam.A rope is attached to the end of the beam at the other end from the axle,and the beam is lifted by the rope so that the beam makes an angle of 30.0 $\degree$ with the horizontal.If the rope is straight up,what magnitude torque does it supply about the axle?

(Multiple Choice)

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Question 37

A gyroscope has a moment of inertia of 0.140 kgm²and has an initial angular speed of 15.0 rad/s.If a lubricant is applied to the bearings of the gyroscope so that frictional torque is reduced to 2.00 x 10^-2 Nm,then in what time interval will the gyroscope coast from 15.0 rad/s to zero?

(Multiple Choice)

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Question 38

Masses are distributed in the xy-plane as follows: 10 kg at (2.0,6.0)m,4.0 kg at (2.0,0.0)m,and 6.0 kg at (0.0,3.0)m.Where would a 20-kg mass need to be positioned so that the center of gravity of the resulting four mass system would be at the origin?

(Multiple Choice)

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Question 39

A ventilation fan with a moment of inertia of 0.034 kgm² has a net torque of 0.11 Nm applied to it.If it starts from rest,what kinetic energy will it have 8.0 s later?

(Multiple Choice)

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(39)

Question 40

Showing 21 - 40 of 86

Exam 8: Rotational Equilibrium and Rotational Dynamics

A baseball pitcher loosens up his pitching arm.He tosses a 0.15-kg ball using only the rotation of his forearm,0.32 m in length,to accelerate the ball.What is the moment of inertia of the ball alone as it moves in a circular arc with a radius of 0.32 m?

Two hoops or rings (I = MR2)are centered,lying on a turntable.The smaller ring has radius = 0.050 m;the larger has radius = 0.10 m.Both have a mass of 3.0 kg.What is the total moment of inertia as the turntable spins? Ignore the mass of the turntable.

A cylinder (I = MR2/2)is rolling along the ground at 7.0 m/s.It comes to a hill and starts going up.Assuming no losses to friction,how high does it get before it stops?

The torque caused by a force F applied at a distance r from the axis of rotation,is given by ,where q is the angle between and .If the magnitudes r and F remain the same,what other angle q¢ will produce the same torque as was produced at angle q if q was less than 90 °\degree° ?

A 100-N uniform ladder,8.0 m long,rests against a smooth vertical wall.The coefficient of static friction between ladder and floor is 0.40.What minimum angle can the ladder make with the floor before it slips?

The quantity "angular momentum" (in terms of the fundamental quantities of mass,length,and time)is equivalent to:

A vault is opened by applying a force of 300 N perpendicular to the plane of the door,0.80 m from the hinges.Find the torque due to this force about an axis through the hinges.

A meter stick is supported by a knife-edge at the 50-cm mark.Doug hangs masses of 0.40 and 0.60 kg from the 20-cm and 80-cm marks,respectively.Where should Doug hang a third mass of 0.30 kg to keep the stick balanced?

An ice skater spins at 2.5 rev/s when his arms are extended.He draws his arms in and spins at 6.0 rev/s.By what factor does his moment of inertia change in the process?

A uniform bridge span weighs 50.0 ´ 103 N and is 40.0 m long.An automobile weighing 15.0 ´ 103 N is parked with its center of gravity located 12.0 m from the right pier.What upward support force does the left pier provide?

An astronaut is on a 100-m lifeline outside a spaceship,circling the ship with an angular speed of 0.100 rad/s.How far inward can she be pulled before the centripetal acceleration reaches 5g = 49 m/s2?

A solid sphere of mass 4.0 kg and radius 0.12 m is at rest at the top of a ramp inclined 15 °\degree° .It rolls to the bottom without slipping.The upper end of the ramp is 1.2 m higher than the lower end.Find the sphere's total kinetic energy when it reaches the bottom.

A gyroscope has a moment of inertia of 0.140 kg*m2 and has an initial angular speed of 15.0 rad/s.If a lubricant is applied to the bearings of the gyroscope so that frictional torque is reduced to 2.00 x 10-2 N*m,then in what time interval will the gyroscope coast from 15.0 rad/s to zero?

Masses are distributed in the xy-plane as follows: 10 kg at (2.0,6.0)m,4.0 kg at (2.0,0.0)m,and 6.0 kg at (0.0,3.0)m.Where would a 20-kg mass need to be positioned so that the center of gravity of the resulting four mass system would be at the origin?

A ventilation fan with a moment of inertia of 0.034 kg*m2 has a net torque of 0.11 N*m applied to it.If it starts from rest,what kinetic energy will it have 8.0 s later?

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Two hoops or rings (I = MR²)are centered,lying on a turntable.The smaller ring has radius = 0.050 m;the larger has radius = 0.10 m.Both have a mass of 3.0 kg.What is the total moment of inertia as the turntable spins? Ignore the mass of the turntable.

A cylinder (I = MR²/2)is rolling along the ground at 7.0 m/s.It comes to a hill and starts going up.Assuming no losses to friction,how high does it get before it stops?

A uniform bridge span weighs 50.0 ´ 10³ N and is 40.0 m long.An automobile weighing 15.0 ´ 10³ N is parked with its center of gravity located 12.0 m from the right pier.What upward support force does the left pier provide?

An astronaut is on a 100-m lifeline outside a spaceship,circling the ship with an angular speed of 0.100 rad/s.How far inward can she be pulled before the centripetal acceleration reaches 5g = 49 m/s²?

A solid sphere of mass 4.0 kg and radius 0.12 m is at rest at the top of a ramp inclined 15 $\degree$ .It rolls to the bottom without slipping.The upper end of the ramp is 1.2 m higher than the lower end.Find the sphere's total kinetic energy when it reaches the bottom.

A gyroscope has a moment of inertia of 0.140 kgm²and has an initial angular speed of 15.0 rad/s.If a lubricant is applied to the bearings of the gyroscope so that frictional torque is reduced to 2.00 x 10^-2 Nm,then in what time interval will the gyroscope coast from 15.0 rad/s to zero?

A ventilation fan with a moment of inertia of 0.034 kgm² has a net torque of 0.11 Nm applied to it.If it starts from rest,what kinetic energy will it have 8.0 s later?